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Sample records for vein blood flow

  1. In vivo analysis of physiological 3D blood flow of cerebral veins

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    Schuchardt, Florian; Schroeder, Laure; Baeuerle, Jochen; Harloff, Andreas [University Medical Centre, Department of Neurology, Freiburg (Germany); Anastasopoulos, Constantin [University Medical Center, Department of Neuropaediatrics and Muscle Disorders, Freiburg (Germany); University Medical Centre, Department of Neuroradiology, Freiburg (Germany); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine and McCormick School of Engineering, Chicago, IL (United States); Hennemuth, Anja; Drexl, Johann [Fraunhofer MEVIS, Bremen (Germany); Valdueza, Jose M. [Neurological Center, Segeberger Kliniken, Bad Segeberg (Germany); Mader, Irina [University Medical Centre, Department of Neuroradiology, Freiburg (Germany)

    2015-08-15

    To visualize and quantify physiological blood flow of intracranial veins in vivo using time-resolved, 3D phase-contrast MRI (4D flow MRI), and to test measurement accuracy. Fifteen healthy volunteers underwent repeated ECG-triggered 4D flow MRI (3 Tesla, 32-channel head coil). Intracranial venous blood flow was analysed using dedicated software allowing for blood flow visualization and quantification in analysis planes at the superior sagittal, straight, and transverse sinuses. MRI was evaluated for intra- and inter-observer agreement and scan-rescan reproducibility. Measurements of the transverse sinuses were compared with transcranial two-dimensional duplex ultrasound. Visualization of 3D blood flow within cerebral sinuses was feasible in 100 % and within at least one deep cerebral vein in 87 % of the volunteers. Blood flow velocity/volume increased along the superior sagittal sinus and was lower in the left compared to the right transverse sinus. Intra- and inter-observer reliability and reproducibility of blood flow velocity (mean difference 0.01/0.02/0.02 m/s) and volume (mean difference 0.0002/-0.0003/0.00003 l/s) were good to excellent. High/low velocities were more pronounced (8 % overestimation/9 % underestimation) in MRI compared to ultrasound. Four-dimensional flow MRI reliably visualizes and quantifies three-dimensional cerebral venous blood flow in vivo and is promising for studies in patients with sinus thrombosis and related diseases. (orig.)

  2. Blood flow parameters in the short gastric vein and splenic vein on Doppler ultrasound reflect gastric variceal bleeding

    International Nuclear Information System (INIS)

    Maruyama, Hitoshi; Ishihara, Takeshi; Ishii, Hiroshi; Tsuyuguchi, Toshio; Yoshikawa, Masaharu; Matsutani, Shoichi; Yokosuka, Osamu

    2010-01-01

    Purpose: Hemodynamic features associated with the bleeding from gastric fundal varices (FV) have not been fully examined. The purpose of this study was to elucidate hemodynamics in the short gastric vein (SGV) which is a major inflow route for FV and flow direction of the splenic vein (SV) in relation to bleeding FV. Materials and Methods: The subject of this retrospective study was 54 cirrhotic patients who had medium- or large-sized FV (20 bleeders, 34 non-bleeders) on endoscopy with SGV on both angiogram and sonogram. Diameter, flow velocity, flow volume of SGV and flow direction in the SV were evaluated by Doppler ultrasound. Results: Diameter, flow velocity and flow volume of SGV were significantly greater in bleeders (9.6 ± 3.1 mm, 11.4 ± 5.2 cm/s, 499 ± 250.1 ml/min) than non-bleeders (6.5 ± 2.2 mm, p = 0.0141; 7.9 ± 3.3 cm/s, p = 0.022; 205 ± 129.1 ml/min, p = 0.0031). SV showed forward flow in 37 (68.5%), to and fro in 3 (5.6%) and reversed flow in 14 patients (25.9%). The frequency of FV bleeding was significantly higher in case with reversed or 'to and fro' SV flow (11/17) than forward SV flow (9/37, p = 0.0043). The cumulative bleeding rate at 3 and 5 years was significantly higher in patients without forward SV flow (38.8% at 3 years, 59.2% at 5 years) than in patients with forward SV flow (18.7% at 3 years, 32.2% at 5 years, p = 0.0199). Conclusion: Advanced SGV blood flow and reversed SV flow direction may be a hemodynamic features closely related to the FV bleeding.

  3. Portal vein blood flow is related to characteristics of the migrating motor complex of the gastrointestinal tract

    DEFF Research Database (Denmark)

    Qvist, Niels; Rafaelsen, Søren Rafael; Troensegaard, P.

    1994-01-01

    Objective: To measure variation in portal blood flow during the interdigestive state in relation to the migrating motor complex (MMC) in healthy volunteers. Design: Portal blood flow was measured by a duplex and colour Doppler technique with 5-min intervals during an entire MMC cycle. Total....... Conclusion: Blood flow in the portal vein varies with the characteristics of the MMC, a relationship which must be considered in future studies in health and disease....

  4. Regional blood flows by the microsphere method: reproducibility in portal hypertensive rats and influence of a portal vein catheter

    International Nuclear Information System (INIS)

    Hadengue, A.; Lee, S.S.; Koshy, A.; Girod, C.; Lebrec, D.

    1988-01-01

    To determine the reproducibility of splanchnic blood flow measurements by the microsphere method in rats with portal hypertension and the effects of laparotomy with portal vein cannulation, eight groups of 10 rats were studied. Microspheres were labelled with 113 Sn or 141 Ce. Laparotomy with portal cannulation had no significant effect in sham-operated rats. In awake portal hypertensive rats, cardiac output and splanchnic blood flow were lower in portal vein cannulated rats compared with those of non-cannulated animals. In anesthetized portal hypertensive rats blood flows were unaffected by portal cannulation, but arterial pressure and heart rate were elevated. Anesthesia also decreased portal pressure in portal hypertensive rats. We conclude that the microsphere method remains reproducible in portal hypertensive rat models. Laparotomy with portal cannulation can alter systemic and splanchnic hemodynamics in portal hypertensive rats; these effects can also be changed during pentobarbital anesthesia. Regional blood flow measurements in portal hypertensive rats should be performed in animals without portal cannulation and preferably in the awake state

  5. The effect of vasopressin on hormone secretion and blood flow from the thyroid vein in sheep with exteriorized thyroids.

    Science.gov (United States)

    Falconer, I R

    1968-12-01

    1. Vasopressin has been shown to activate the thyroid in some species, and also to be released into the bloodstream after emotional and other stresses.2. Emotional stimuli applied to sheep have previously been shown to increase thyroid secretion and the possible influence of vasopressin in this process has been investigated. Sheep bearing exteriorized thyroid glands were used, so that thyroid vein blood could be collected in undisturbed conscious animals.3. (125)I or (131)I (50 muc) was injected I.M. into the sheep; 4-7 days later, samples of thyroid vein blood were collected at 10 min intervals for 4 hr, and the concentration of total and protein bound (125)I or (131)I was measured. Intravenous infusions of 0.3, 3.0 or 31 m-u./min arginine or lysine vasopressin, or close arterial infusions of 3.0 or 31 m-u./min arginine vasopressin were administered 1.5 hr after commencement of blood sampling. Blood flow from the thyroid was measured by a plethysmographic technique during similar experiments.4. No significant changes in thyroid hormone secretion were observed as a result of vasopressin infusion, and it was concluded that vasopressin release does not play a part in the activation of the thyroid resulting from emotional stimulus in the sheep.

  6. Phase-contrast MR assessment of pulmonary venous blood flow in children with surgically repaired pulmonary veins

    International Nuclear Information System (INIS)

    Valsangiacomo, Emanuela R.; Yoo, Shi-Joon; Barrea, Catherine; Smallhorn, Jeffrey F.; Macgowan, Christopher K.; Coles, John G.

    2003-01-01

    Pulmonary venous (PV) obstruction may complicate surgical repair of PV abnormalities. By combining phase-contrast cine (PC) imaging and contrast-enhanced angiography, magnetic resonance (MR) imaging can provide physiological information complementing anatomical diagnosis. To compare the PV flow pattern observed after surgical repair of PV abnormalities with normal PV flow pattern and to investigate the changes occurring in the presence of PV stenosis by using PC MR in children. By using PC MR, PV flow was evaluated in 14 patients (3 months-14 years) who underwent surgical repair for PV abnormalities. Eleven children (8-18 years) were studied as normal controls. Peak flow velocities and patterns were compared among three groups: normal veins (n=23), surgically repaired veins without (n=44) and with stenosis (n=10). Normal and unobstructed pulmonary veins after surgery showed a biphasic or triphasic flow pattern with one or two systolic peaks and a diastolic peak. Unobstructed surgically repaired veins showed decreased peak systolic velocity (P =0.001) and an increased peak diastolic velocity (P=0.005) when compared to normal values. Obstructed veins showed decreased systolic and diastolic velocities when measured upstream from the stenosis. PC MR shows different flow patterns among normal, surgically repaired pulmonary veins with and without stenosis. (orig.)

  7. Blood flow velocity in the Popliteal Vein using Transverse Oscillation Ultrasound

    DEFF Research Database (Denmark)

    Bechsgaard, Thor; Lindskov Hansen, Kristoffer; Brandt, Andreas Hjelm

    2016-01-01

    . Transverse Oscillation US (TOUS), a non-invasive angle independent method, has been implemented on a commercial scanner. TOUS’s advantage compared to SDUS is a more elaborate visualization of complex flow. The aim of this study was to evaluate, whether TOUS perform equal to SDUS for recording velocities...

  8. A Study on Effects of the Transient Compression by Tightly Tied Necktie on Blood Flow in the Internal Jugular Veins Using 2D-PC MRA

    International Nuclear Information System (INIS)

    Kim, Keung Sik; Chung, Tae Sub; Lee, Bum Soo; Park, In Kook; Kim, Hyun Soo; Yoo, Beong Gyu

    2008-01-01

    The 25 healthy male volunteers aged from 20 to 50 years old have been employed in this study. 2D-PC MRA was performed to measure the velocity of the blood flow in the internal carotid artery and internal jugular veins using 3.0T MRI Whole body (signa VH/i GE). ECTRICKS-CEMRA was performed to evaluate the pattern of blood circulation from internal carotid artery to internal jugular vein. Using 2D-PC MRA, the cross-section of the 4th and 5th cervical discs was scanned with 24 cm FOV. Then the speed of blood flow was measured for internal carotid artery and internal jugular vein when the subject wears a necktie tightly and no tie. The average of maximum velocity of internal carotid arteries without a necktie was 72.13 cm/sec in the right side and 74.96 cm/sec in the left side (average 73.54 cm/sec in both sides) while the average of maximum velocity of internal jugular veins without a necktie was -34.45 cm/sec in the right side and -24.99 cm/sec in the left side (-29.72 cm/sec in both sides). However, when wearing a necktie tightly, the average of maximum velocity of internal carotid arteries was 61.35 cm/sec in the right side and 65.19 cm/sec in the left side (average 63.27 cm/sec in both sides) while the average of maximum velocity of internal jugular veins was -22.14 cm/sec in the right side and -17.93 cm/sec in the left side (-20.03 cm/sec in both sides). With the necktie tightly knotted, the average blood flow speed of both internal carotid arteries slightly decreased to 86% (63.27/73.54 cm/sec) compared to no tie case in which both internal jugularveins significantly went down to 67% (-20.03/-29.72 cm/sec). Thus it is suggested that wearing a necktie affects the circulation of internal jugular veins (33% decrease in blood flow speed) more significantly than that of internal carotid artery (14% decrease in blood flow speed). Without a necktie, ECTRICKS-CEMRA showed natural blood circulation patterns of internal carotid arteries and internal jugular veins without

  9. Blood sampling from adrenal gland vein

    International Nuclear Information System (INIS)

    Sun Yong; Ni Caifang

    2009-01-01

    Adrenal gland vein sampling is an interventional method to get the blood samples from the adrenal gland vein. The blood is obtained via a catheter which is selectively inserted in the adrenal gland vein. This technique is mainly used to be diagnostic for primary hyperaldosteronism. A full knowledge of the anatomy and variations of the adrenal gland vein, serious preoperative preparation and skilled catheterization manipulation are necessary for obtaining sufficient blood sample and for reducing the occurrence of complications. Providing the physicians with definite diagnostic evidence and being technically feasible, adrenal gland vein sampling should become one of the routine examinations for clarifying the cause of primary hyperaldosteronism. (authors)

  10. Role of the cyclooxygenase 2-thromboxane pathway in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced decrease in mesencephalic vein blood flow in the zebrafish embryo

    International Nuclear Information System (INIS)

    Teraoka, Hiroki; Kubota, Akira; Dong, Wu; Kawai, Yusuke; Yamazaki, Koji; Mori, Chisato; Harada, Yoshiteru; Peterson, Richard E.; Hiraga, Takeo

    2009-01-01

    Previously, we reported that 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) evoked developmental toxicity required activation of aryl hydrocarbon receptor type 2 (AHR2), using zebrafish embryos. However, the downstream molecular targets of AHR2 activation are largely unknown and are the focus of the present investigation. TCDD induces cyclooxygenase 2 (COX2), a rate-limiting enzyme for prostaglandin synthesis in certain cells. In the present study, we investigated the role of the COX2-thromboxane pathway in causing a specific endpoint of TCDD developmental toxicity in the zebrafish embryo, namely, a decrease in regional blood flow in the dorsal midbrain. It was found that the TCDD-induced reduction in mesencephalic vein blood flow was markedly inhibited by selective COX2 inhibitors, NS-398 and SC-236, and by a general COX inhibitor, indomethacin, but not by a selective COX1 inhibitor, SC-560. Gene knock-down of COX2 by two different types of morpholino antisense oligonucleotides, but not by their negative homologs, also protected the zebrafish embryos from mesencephalic vein circulation failure caused by TCDD. This inhibitory effect of TCDD on regional blood flow in the dorsal midbrain was also blocked by selective antagonists of the thromboxane receptor (TP). Treatment of control zebrafish embryos with a TP agonist also caused a reduction in mesencephalic vein blood flow and it too was blocked by a TP antagonist, without any effect on trunk circulation. Finally, gene knock-down of thromboxane A synthase 1 (TBXS) with morpholinos but not by the morpholinos' negative homologs provided significant protection against TCDD-induced mesencephalic circulation failure. Taken together, these results point to a role of the prostanoid synthesis pathway via COX2-TBXS-TP in the local circulation failure induced by TCDD in the dorsal midbrain of the zebrafish embryo

  11. Role of zebrafish cytochrome P450 CYP1C genes in the reduced mesencephalic vein blood flow caused by activation of AHR2

    International Nuclear Information System (INIS)

    Kubota, Akira; Stegeman, John J.; Woodin, Bruce R.; Iwanaga, Toshihiko; Harano, Ryo; Peterson, Richard E.; Hiraga, Takeo; Teraoka, Hiroki

    2011-01-01

    2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) causes various signs of toxicity in early life stages of vertebrates through activation of the aryl hydrocarbon receptor (AHR). We previously reported a sensitive and useful endpoint of TCDD developmental toxicity in zebrafish, namely a decrease in blood flow in the dorsal midbrain, but downstream genes involved in the effect are not known. The present study addressed the role of zebrafish cytochrome P450 1C (CYP1C) genes in association with a decrease in mesencephalic vein (MsV) blood flow. The CYP1C subfamily was recently discovered in fish and includes the paralogues CYP1C1 and CYP1C2, both of which are induced via AHR2 in zebrafish embryos. We used morpholino antisense oligonucleotides (MO or morpholino) to block initiation of translation of the target genes. TCDD-induced mRNA expression of CYP1Cs and a decrease in MsV blood flow were both blocked by gene knockdown of AHR2. Gene knockdown of CYP1C1 by two different morpholinos and CYP1C2 by two different morpholinos, but not by their 5 nucleotide-mismatch controls, was effective in blocking reduced MsV blood flow caused by TCDD. The same CYP1C-MOs prevented reduction of blood flow in the MsV caused by β-naphthoflavone (BNF), representing another class of AHR agonists. Whole-mount in situ hybridization revealed that mRNA expression of CYP1C1 and CYP1C2 was induced by TCDD most strongly in branchiogenic primordia and pectoral fin buds. In situ hybridization using head transverse sections showed that TCDD increased the expression of both CYP1Cs in endothelial cells of blood vessels, including the MsV. These results indicate a potential role of CYP1C1 and CYP1C2 in the local circulation failure induced by AHR2 activation in the dorsal midbrain of the zebrafish embryo. - Research Highlights: → We examine the roles of zebrafish CYP1C1 and CYP1C2 in TCDD developmental toxicity. → TCDD induces mRNA expression of both CYP1Cs in the mesencephalic vein. → Knockdown of each

  12. Influence of acute jugular vein compression on the cerebral blood flow velocity, pial artery pulsation and width of subarachnoid space in humans.

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    Andrzej F Frydrychowski

    Full Text Available PURPOSE: The aim of this study was to assess the effect of acute bilateral jugular vein compression on: (1 pial artery pulsation (cc-TQ; (2 cerebral blood flow velocity (CBFV; (3 peripheral blood pressure; and (4 possible relations between mentioned parameters. METHODS: Experiments were performed on a group of 32 healthy 19-30 years old male subjects. cc-TQ and the subarachnoid width (sas-TQ were measured using near-infrared transillumination/backscattering sounding (NIR-T/BSS, CBFV in the left anterior cerebral artery using transcranial Doppler, blood pressure was measured using Finapres, while end-tidal CO(2 was measured using medical gas analyser. Bilateral jugular vein compression was achieved with the use of a sphygmomanometer held on the neck of the participant and pumped at the pressure of 40 mmHg, and was performed in the bend-over (BOPT and swayed to the back (initial position. RESULTS: In the first group (n = 10 during BOPT, sas-TQ and pulse pressure (PP decreased (-17.6% and -17.9%, respectively and CBFV increased (+35.0%, while cc-TQ did not change (+1.91%. In the second group, in the initial position (n = 22 cc-TQ and CBFV increased (106.6% and 20.1%, respectively, while sas-TQ and PP decreases were not statistically significant (-15.5% and -9.0%, respectively. End-tidal CO(2 remained stable during BOPT and venous compression in both groups. Significant interdependence between changes in cc-TQ and PP after bilateral jugular vein compression in the initial position was found (r = -0.74. CONCLUSIONS: Acute bilateral jugular venous insufficiency leads to hyperkinetic cerebral circulation characterised by augmented pial artery pulsation and CBFV and direct transmission of PP into the brain microcirculation. The Windkessel effect with impaired jugular outflow and more likely increased intracranial pressure is described. This study clarifies the potential mechanism linking jugular outflow insufficiency with arterial small vessel cerebral

  13. Hepatic vein flow pattern in children: assesment with Doppler sonography

    International Nuclear Information System (INIS)

    Ahmetoglu, Ali; Kosucu, Polat; Arikan, Elif; Dinc, Hasan; Resit Guemele, Halit

    2005-01-01

    Background: Aim of this study is to establish normal hepatic vein flow pattern and effect of age, sex, activity and feeding status on the hepatic flow pattern in normal Turkish children less than 15 years of ages and also to compare our values with the previously reported studies. Method: Hepatic vein flow patterns were evaluated in 150 children (83 male, 67 female) without any cardiac, pulmonary and liver disease by using Doppler sonography. Blood flow patterns were compared with age, sex, activity, and feeding status of the children. Results: Only 44% of the children had triphasic flow pattern in all hepatic veins. Monophasic flow pattern was the most common flow pattern in children less then 1 year of age. Triphasic flow pattern increase after 1 year of age. Although most of the children older than 1 year of age had triphasic flow pattern, there is some variation in the flow patterns of the hepatic veins in the same subject. Triphasic hepatic flow pattern is most commonly seen in the left hepatic vein and least commonly seen in the right hepatic vein. There was no significant difference between male and girl, children who were agitated or calm and fasting or not fasting in respect to triphasic flow pattern. Conclusion: Liver stiffening is not only the reason for abnormal hepatic flow pattern and some other physiologic factors may also lead to mono and/or diphasic flow pattern in the children. Absence of triphasic flow pattern must not be accepted as a liver pathology in children especially younger than 1 year of age

  14. [Portal perfusion with right gastroepiploic vein flow in liver transplant].

    Science.gov (United States)

    Mendoza-Sánchez, Federico; Javier-Haro, Francisco; Mendoza-Medina, Diego Federico; González-Ojeda, Alejandro; Cortés-Lares, José Antonio; Fuentes-Orozco, Clotilde

    Liver transplantation in patients with liver cirrhosis, portal vein thrombosis, and cavernous transformation of the portal vein, is a complex procedure with high possibility of liver graft dysfunction. It is performed in 2-19% of all liver transplants, and has a significantly high mortality rate in the post-operative period. Other procedures to maintain portal perfusion have been described, however there are no reports of liver graft perfusion using right gastroepiploic vein. A 20 year-old female diagnosed with cryptogenic cirrhosis, with a Child-Pugh score of 7 points (class "B"), and MELD score of 14 points, with thrombosis and cavernous transformation of the portal vein, severe portal hypertension, splenomegaly, a history of upper gastrointestinal bleeding due to oesophageal varices, and left renal agenesis. The preoperative evaluation for liver transplantation was completed, and the right gastroepiploic vein of 1-cm diameter was observed draining to the infrahepatic inferior vena cava and right suprarenal vein. An orthotopic liver transplantation was performed from a non-living donor (deceased on January 30, 2005) using the Piggy-Back technique. Portal vein perfusion was maintained using the right gastroepiploic vein, and the outcome was satisfactory. The patient was discharged 13 days after surgery. Liver transplantation was performed satisfactorily, obtaining an acceptable outcome. In this case, the portal perfusion had adequate blood flow through the right gastroepiploic vein. Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  15. The effect of partial portal decompression on portal blood flow and effective hepatic blood flow in man: a prospective study.

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    Rosemurgy, A S; McAllister, E W; Godellas, C V; Goode, S E; Albrink, M H; Fabri, P J

    1995-12-01

    With the advent of transjugular intrahepatic porta-systemic stent shunt and the wider application of the surgically placed small diameter prosthetic H-graft portacaval shunt (HGPCS), partial portal decompression in the treatment of portal hypertension has received increased attention. The clinical results supporting the use of partial portal decompression are its low incidence of variceal rehemorrhage due to decreased portal pressures and its low rate of hepatic failure, possibly due to maintenance of blood flow to the liver. Surprisingly, nothing is known about changes in portal hemodynamics and effective hepatic blood flow following partial portal decompression. To prospectively evaluate changes in portal hemodynamics and effective hepatic blood flow brought about by partial portal decompression, the following were determined in seven patients undergoing HGPCS: intraoperative pre- and postshunt portal vein pressures and portal vein-inferior vena cava pressure gradients, intraoperative pre- and postshunt portal vein flow, and pre- and postoperative effective hepatic blood flow. With HGPCS, portal vein pressures and portal vein-inferior vena cava pressure gradients decreased significantly, although portal pressures remained above normal. In contrast to the significant decreases in portal pressures, portal vein blood flow and effective hepatic blood flow do not decrease significantly. Changes in portal vein pressures and portal vein-inferior vena cava pressure gradients are great when compared to changes in portal vein flow and effective hepatic blood flow. Reduction of portal hypertension with concomitant maintenance of hepatic blood flow may explain why hepatic dysfunction is avoided following partial portal decompression.

  16. Continuous Perfusion of Saphenous Vein by Oxygenated Blood during Beating Coronary Surgery

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    Mohammad Hossein Mandegar

    2015-09-01

    Full Text Available Background: The saphenous vein remains the most commonly used conduit for coronary artery bypass surgery (CABG. However, the long-term success of surgical revascularization is largely limited by development of occlusion in vein grafts. Objectives: We sought to reduce graft ischemia by maintaining the blood flow into the harvested vein throughout surgery at lowest costs and without special devices. Patients and Methods: This study was conducted on three hundred patients aged 58.5 ± 8 years undergoing elective first-time off-pump CABG with saphenous veins. Results: In addition to preserving nutritional materials and oxygen, the veins harvested via this novel technique did not go into spasm and were not subjected to high-pressure distension, eventually resulting in minimal damage to the endothelium. Conclusions: This technique confers favorable myocardial function and protection in the presence of left ventricular dysfunction, especially in elderly patients.

  17. Testicular blood flow in varicocele

    International Nuclear Information System (INIS)

    Iwamoto, Teruaki; Hirokawa, Makoto.

    1986-01-01

    Radioisotopic scrotal angiography was applied for study of testicular blood flow of patients with varicocele. Following iv. bolus injection of 10 ∼ 20 mCi of Tc human serum albumine, Tc RBC or Tc pertechnetate, time activity curve of radioactivity at corresponding bilateral areas of scrotum was simultaneously generated and compared. Eighty-four patients with overt varicocele (grade 2 and 3) at left side only, were selected for the present study and eight healthy young volunteers were studied as a control group. Three patterns of time activity curves were recognized. They are as follows. Type 1, where radioactivity was accumulated quickly in left side and then decreased gradually. Bilateral time activity curves were asymmetrical. Type 2, where time activity curves rose gradually and to a higher level at the left side than at the right side. Type 3, where bilateral time activity curves increased gradually, and symmetrically. All of the control group showed the same pattern as Type 3. Of the 84 patients examined, 34 patients showed Type 1, including 7 with grade 2 and 27 with grade 3. Twenty-four patients showed Type 2. consisting of 12 with grade 2 and 12 with grade 3. Twenty-six patients showed Type 3, consisting of 14 with grade 2 and 12 with grade 3. We presumed the following about testicular blood flow in varicocele: Type 1 pattern shows retrograde blood flow from the renal vein to the internal spermatic vein, Type 2 pattern shows poor venous return through the internal spermatic vein and Type 3 pattern shows good venous return though the presence of dilatated pampiniform plexus. (author)

  18. The effect of intravitreal bevacizumab on ocular blood flow in diabetic retinopathy and branch retinal vein occlusion as measured by laser speckle flowgraphy

    Directory of Open Access Journals (Sweden)

    Nitta F

    2014-06-01

    Full Text Available Fumihiko Nitta,1 Hiroshi Kunikata,1,2 Naoko Aizawa,1 Kazuko Omodaka,1 Yukihiro Shiga,1 Masayuki Yasuda,1 Toru Nakazawa1–31Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan; 2Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan; 3Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, JapanBackground: This study evaluated the effect of intravitreal injection of bevacizumab (IVB on macular edema associated with diabetic retinopathy (DME or branch retinal vein occlusion (BRVOME using laser speckle flowgraphy.Methods: A comparative interventional study of 25 eyes from 22 patients with macular edema (DME group: 12 eyes; BRVOME group: 13 eyes who underwent IVB. Mean blur rate (MBR was measured in the retinal artery, retinal vein, optic nerve head (ONH, and choroid before and after IVB. Results: In the BRVOME group, there was no significant change in MBR in the retinal artery, retinal vein or ONH, but choroidal MBR decreased significantly (P=0.04. In the DME group, the MBR in the retinal artery, retinal vein, ONH, and choroid decreased significantly (P=0.02, P=0.04, P<0.001, and P=0.04, respectively. In the DME group, pre-IVB MBR in the ONH was significantly correlated with post-IVB foveal thickness (R= -0.71, P=0.002. There was no such correlation in the BRVOME group in the ONH.Conclusion: IVB had a suppressive effect on circulation in eyes with DME but not in those with BRVOME. This suggests that this noninvasive and objective biomarker may be a useful part of pre-IVB evaluations and decision-making in DME.Keywords: macular edema, mean blur rate, optic nerve head, biomarker, ocular circulation

  19. The pathology of facial vein blood sampling in mice

    DEFF Research Database (Denmark)

    Hansen, Ket; Harslund, Jakob le Fèvre; Bollen, Peter

    2014-01-01

    vein blood sampling. Therefore, we investigated if this technique was associated with pathological changes of the jaw region. Methods: 43 NMRI mice were subjected to facial vein blood sampling by using the lancet method during 12 months, starting at the age of 8 weeks. The mice were restrained manually......, and the tissue of the jaw was evaluated. Results: In the 23 mice, from which blood samples had been taken 2 days previously, 5 mice had no signs of gross pathological changes, whereas 12 mice had signs of minimal local subcutaneous bleeding and 6 mice had moderate local subcutaneous bleeding. No additional gross...... pathological changes were observed. In the 23 mice, from which blood samples had been taken 4 weeks earlier, no hemorrhage or signs of scar tissue formation could be observed. Histological slides are currently being processed (HE staining) and will be evaluated and discussed....

  20. The effects of vasoactive agents on flow through saphenous vein grafts during lower-extremity peripheral vascular surgery.

    Science.gov (United States)

    Maslow, Andrew D; Bert, Arthur; Slaiby, Jeffrey; Carney, William; Marcaccio, Edward

    2007-06-01

    The purpose of this study was to assess the effects of hemodynamic alterations on vein graft flow during peripheral vascular surgery. It was hypothesized that vasopressors can be administered without compromising flow through the vein grafts. Tertiary care center, university medical center. Randomized placebo-controlled double-blinded study. The effects of phenylephrine, epinephrine, milrinone, intravenous fluid, and placebo on newly constructed peripheral vein grafts were assessed in 60 patients (12 patients in each of 5 groups). Systemic and central hemodynamics were measured by using intra-arterial and pulmonary artery catheters. Vein graft flow was measured by using a transultrasonic flow probe (Transultrasonic Inc, Ithaca, NY). Phenylephrine increased systemic mean blood pressure (mBP) (68.2-94.0 mmHg, p < 0.01), systemic vascular resistance (SVR) (1,091-1,696 dynes x sec x cm(-5), p < 0.001), and vein graft flow (39.5-58.9 mL/min, p < 0.01), whereas cardiac output remained unchanged. Epinephrine resulted in increased cardiac output (4.4-6.9 L/min, p < 0.01) and mBP (72.7-89.1 mmHg, p < 0.01), whereas vein graft flow was reduced in 6 of 12 patients. Intravenous fluid administration resulted in a relatively smaller increase in graft flow (37.6-46.0 mL/min, p < 0.05), an increase in cardiac output, and an insignificant decrease in SVR. Other treatments had either little or no effect on vein graft flow. The study hypothesis was partly supported. Although both phenylephrine and epinephrine increased blood pressure, only the former increased vein graft flow in all patients. In conjunction with increases in graft flow after fluid administration, these data suggest that factors affecting vein graft flow are not just simply related to systemic hemodynamics.

  1. Effect of obstructive jaundice on hepatic hemodynamics: use of Sonazoid-enhanced ultrasonography in a prospective study of the blood flow balance between the hepatic portal vein and hepatic artery.

    Science.gov (United States)

    Wakui, Noritaka; Takeda, Yuki; Nishinakagawa, Shuta; Ueki, Nobuo; Otsuka, Takafumi; Oba, Nobuyuki; Hashimoto, Hiroshi; Kamiyama, Naohisa; Sumino, Yasukiyo; Kojima, Tatsuya

    2015-10-01

    To prospectively clarify the effects of obstructive jaundice (OJ) on hepatic hemodynamics using contrast-enhanced ultrasonography (US). Subjects comprised 14 patients admitted to our hospital for OJ between April 2013 and March 2014. Contrast-enhanced US was performed using the LOGIQ E9 ultrasound device during the jaundice phase, before biliary drainage, and again after improvement of jaundice. After injecting the Sonazoid contrast agent, contrast dynamics were recorded in the right kidney and liver segments 5 or 6. Prototype software was used to calculate mean arrival time (AT) of the contrast agent in the liver parenchyma. Statistical analysis was performed to compare the mean AT in the jaundice and improved jaundice phases. We were unable to follow up three of the 14 patients after biliary drainage; thus, we included 11 patients for further analysis. The mean AT of the contrast agent was 2.0 ± 1.8 and 6.1 ± 2.3 s in the jaundice and improved jaundice phases, respectively, showing significantly shorter AT in the jaundice phase (p = 0.0033). Our findings indicate that OJ may influence the blood flow balance between the hepatic portal vein and hepatic artery.

  2. Reversal of flow in the inferior vena cava and hepatic veins on dynamic CT

    International Nuclear Information System (INIS)

    Lelij, H. van der; Mallens, W.M.C.

    1988-01-01

    A tricuspid insufficiency may not be clinically evident and may remain unknown to the clinician. The phenomenon of a reversal of inferior vena caval blood flow and hepatic veins is known to occur in tricuspid regurgitation from right ventricular angiography and duplex scanning. Demonstration of such a reversal flow on a dynamic CT scan, as in our case, has, to our knowledge, not as yet been reported

  3. Blood vessel classification into arteries and veins in retinal images

    Science.gov (United States)

    Kondermann, Claudia; Kondermann, Daniel; Yan, Michelle

    2007-03-01

    The prevalence of diabetes is expected to increase dramatically in coming years; already today it accounts for a major proportion of the health care budget in many countries. Diabetic Retinopathy (DR), a micro vascular complication very often seen in diabetes patients, is the most common cause of visual loss in working age population of developed countries today. Since the possibility of slowing or even stopping the progress of this disease depends on the early detection of DR, an automatic analysis of fundus images would be of great help to the ophthalmologist due to the small size of the symptoms and the large number of patients. An important symptom for DR are abnormally wide veins leading to an unusually low ratio of the average diameter of arteries to veins (AVR). There are also other diseases like high blood pressure or diseases of the pancreas with one symptom being an abnormal AVR value. To determine it, a classification of vessels as arteries or veins is indispensable. As to our knowledge despite the importance there have only been two approaches to vessel classification yet. Therefore we propose an improved method. We compare two feature extraction methods and two classification methods based on support vector machines and neural networks. Given a hand-segmentation of vessels our approach achieves 95.32% correctly classified vessel pixels. This value decreases by 10% on average, if the result of a segmentation algorithm is used as basis for the classification.

  4. Pressure-flow characteristics and nutritional capacity of coronary veins in dogs

    International Nuclear Information System (INIS)

    Cohen, M.V.; Matsuki, T.; Downey, J.M.

    1988-01-01

    To examine the hemodynamic interdependence of coronary arteries and veins, great cardiac vein (GCV) and left anterior descending (LAD) coronary artery flows of dogs were measured. Although they were not different under base-line conditions, 42.9 +/- 4.1 and 34.9 +/- 5.2 ml/min, respectively, LAD occlusion caused only a 56% decrease in GCV flow, whereas peak GCV flow during reactive hyperemia consistently underestimated peak LAD flow by nearly 40%. The measured hemodynamic data were very closely predicted by a simple model that assumed the presence of a low-resistance venous collateral anastomotic pathway between the GCV and veins outside the LAD territory. The resistance of the venous collaterals averaged 9.9 +/- 3.0% of LAD resistance. Therefore, GCV flow does not solely represent LAD collateral flow when the LAD is occluded, nor is it a reliable indicator of changes in LAD perfusion patterns. Nutritional myocardial perfusion assessed with 133 Xe washout decreased from 0.86 +/- 0.16 to 0.13 +/- 0.02 ml.min-1.g-1 after LAD occlusion, whereas retroperfusion of the GCV with arterial blood enhanced washout by 85% to 0.23 +/- 0.03 ml.min-1.g-1 (P less than 0.005). Retroperfusion was inefficient, however, since only 10% of the isotope injected into the GCV gained access to the myocardium

  5. Blood flow patterns underlie developmental heart defects.

    Science.gov (United States)

    Midgett, Madeline; Thornburg, Kent; Rugonyi, Sandra

    2017-03-01

    Although cardiac malformations at birth are typically associated with genetic anomalies, blood flow dynamics also play a crucial role in heart formation. However, the relationship between blood flow patterns in the early embryo and later cardiovascular malformation has not been determined. We used the chicken embryo model to quantify the extent to which anomalous blood flow patterns predict cardiac defects that resemble those in humans and found that restricting either the inflow to the heart or the outflow led to reproducible abnormalities with a dose-response type relationship between blood flow stimuli and the expression of cardiac phenotypes. Constricting the outflow tract by 10-35% led predominantly to ventricular septal defects, whereas constricting by 35-60% most often led to double outlet right ventricle. Ligation of the vitelline vein caused mostly pharyngeal arch artery malformations. We show that both cardiac inflow reduction and graded outflow constriction strongly influence the development of specific and persistent abnormal cardiac structure and function. Moreover, the hemodynamic-associated cardiac defects recapitulate those caused by genetic disorders. Thus our data demonstrate the importance of investigating embryonic blood flow conditions to understand the root causes of congenital heart disease as a prerequisite to future prevention and treatment. NEW & NOTEWORTHY Congenital heart defects result from genetic anomalies, teratogen exposure, and altered blood flow during embryonic development. We show here a novel "dose-response" type relationship between the level of blood flow alteration and manifestation of specific cardiac phenotypes. We speculate that abnormal blood flow may frequently underlie congenital heart defects. Copyright © 2017 the American Physiological Society.

  6. Evaluating ocular blood flow

    Directory of Open Access Journals (Sweden)

    Jyotsna Maram

    2017-01-01

    Full Text Available Studies have shown that vascular impairment plays an important role in the etiology and pathogenesis of various ocular diseases including glaucoma, age-related macular degeneration, diabetic retinopathy, and retinal venous occlusive disease. Thus, qualitative and quantitative assessment of ocular blood flow (BF is a topic of interest for early disease detection, diagnosis, and management. Owing to the rapid improvement in technology, there are several invasive and noninvasive techniques available for evaluating ocular BF, with each of these techniques having their own limitations and advantages. This article reviews these important techniques, with a particular focus on Doppler Fourier domain optical coherence tomography (OCT and OCT-angiography.

  7. C1-esterase inhibitor protects against early vein graft remodeling under arterial blood pressure.

    Science.gov (United States)

    Krijnen, Paul A J; Kupreishvili, Koba; de Vries, Margreet R; Schepers, Abbey; Stooker, Wim; Vonk, Alexander B A; Eijsman, Leon; Van Hinsbergh, Victor W M; Zeerleder, Sacha; Wouters, Diana; van Ham, Marieke; Quax, Paul H A; Niessen, Hans W M

    2012-01-01

    Arterial pressure induced vein graft injury can result in endothelial loss, accelerated atherosclerosis and vein graft failure. Inflammation, including complement activation, is assumed to play a pivotal role herein. Here, we analyzed the effects of C1-esterase inhibitor (C1inh) on early vein graft remodeling. Human saphenous vein graft segments (n=8) were perfused in vitro with autologous blood either supplemented or not with purified human C1inh at arterial pressure for 6h. The vein segments and perfusion blood were analyzed for cell damage and complement activation. In addition, the effect of purified C1inh on vein graft remodeling was analyzed in vivo in atherosclerotic C57Bl6/ApoE3 Leiden mice, wherein donor caval veins were interpositioned in the common carotid artery. Application of C1inh in the in vitro perfusion model resulted in significantly higher blood levels and significantly more depositions of C1inh in the vein wall. This coincided with a significant reduction in endothelial loss and deposition of C3d and C4d in the vein wall, especially in the circular layer, compared to vein segments perfused without supplemented C1inh. Administration of purified C1inh significantly inhibited vein graft intimal thickening in vivo in atherosclerotic C57Bl6/ApoE3 Leiden mice, wherein donor caval veins were interpositioned in the common carotid artery. C1inh significantly protects against early vein graft remodeling, including loss of endothelium and intimal thickening. These data suggest that it may be worth considering its use in patients undergoing coronary artery bypass grafting. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  8. Flow velocity change in the cortical vein during motor activation and its effect on functional brain MRI

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Kazuhiro [Kyoto Prefectural Univ. of Medicine (Japan)

    1998-06-01

    On the brain functional magnetic resonance imaging (fMRI) using the gradient-recalled echo technique with clinical MR scanner, the activated areas nearly correspond with the cortical veins. This suggests that the fMRI signal mainly originates from the cortical veins. In this study, we analyzed the flow velocity in the cortical vein quantitatively during brain activation and resting status using 2 dimensional time-of-flight cine MR venography (2D-TOF-cine-MRV) and 2 dimensional phase contrast MRV (2D-PC-MRV) techniques, and demonstrated that the flow velocity increased in the cortical vein corresponding to the activated area during activation status. The increase of flow velocity was calculated to be about 20%. The reason for the increased flow velocity is probably due to the increased regional cerebral blood flow and volume in the activated area. We should be careful to analyze the data of the fMRI because the flow velocity affects the fMRI signal such as the inflow effect and the oblique flow effect. When using the gradient echo method, the effect of the flow velocity is one of the important factors of the fMRI signal. (author)

  9. In vivo evaluation of femoral blood flow measured with magnetic resonance

    DEFF Research Database (Denmark)

    Henriksen, O; Ståhlberg, F; Thomsen, C

    1989-01-01

    , corrected for the T2 decay of non-flowing blood was used to calculate the blood flow. As a reference, the blood flow in the femoral artery was measured simultaneously with an invasive indicator dilution technique. T2 of non-flowing blood was measured in vivo in popliteal veins during regional circulatory...... arrest. The mean T2 of non-flowing blood was found to be 105 +/- 31 ms. The femoral blood flow ranged between 0 and 643 ml/min measured with MRI and between 280 and 531 ml/min measured by the indicator dilution technique. There was thus poor agreement between the two methods. The results indicate......Quantitative measurements of blood flow based on magnetic resonance imaging (MRI) using conventional multiple spin echo sequences were evaluated in vivo in healthy young volunteers. Blood flow was measured using MRI in the femoral vein. The initial slope of the multiple spin echo decay curve...

  10. Preventing Deep Vein Thrombosis

    Science.gov (United States)

    ... Physicians Contact Us My ACOG ACOG Departments Donate Shop Career Connection Home Clinical Guidance & Publications Practice Management ... skin. A clot also can form if blood flow is too slow the lining of a vein ...

  11. The effect of ultrasound on arterial blood flow: 1. Steady fully developed flow

    International Nuclear Information System (INIS)

    Bestman, A.R.

    1990-12-01

    The paper models the effects of ultrasound heating of the tissues and the resultant perturbation on blood flow in the arteries and veins. It is assumed that the blood vessel is rigid and the undisturbed flow is fully developed. Acoustical perturbation on this Poiseuille flow, for the general three-dimensional flow with heat transfer in an infinitely long pipe is considered. Closed form analytical solutions are obtained to the problem. It is discovered that the effects of the ultrasound heating are concentrated at the walls of the blood vessels. (author). 4 refs

  12. Numerical simulation of human blood flow in microvessels

    International Nuclear Information System (INIS)

    Attaullah; Chughtai, I.R.; Nadeem, M.

    2009-01-01

    In this research, steady state flow of human blood in vascular system has been studied. Computational fluid dynamics has been used to predict pressure drop in human arteriole, artery, capillary, venule and vein. Viscosity of human blood has been treated in different ways by employing Newtonian, Power law and Herschel-Bulkley models. It has been observed that the Herschel-Bulkley model predicts the pressure gradients in all diameters reasonably whereas Newtonian and Power laws have their limitations. (author)

  13. PX-18 Protects Human Saphenous Vein Endothelial Cells under Arterial Blood Pressure.

    Science.gov (United States)

    Kupreishvili, Koba; Stooker, Wim; Emmens, Reindert W; Vonk, Alexander B A; Sipkens, Jessica A; van Dijk, Annemieke; Eijsman, Leon; Quax, Paul H; van Hinsbergh, Victor W M; Krijnen, Paul A J; Niessen, Hans W M

    2017-07-01

    Arterial blood pressure-induced shear stress causes endothelial cell apoptosis and inflammation in vein grafts after coronary artery bypass grafting. As the inflammatory protein type IIA secretory phospholipase A 2 (sPLA 2 -IIA) has been shown to progress atherosclerosis, we hypothesized a role for sPLA 2 -IIA herein. The effects of PX-18, an inhibitor of both sPLA 2 -IIA and apoptosis, on residual endothelium and the presence of sPLA 2 -IIA were studied in human saphenous vein segments (n = 6) perfused at arterial blood pressure with autologous blood for 6 hrs. The presence of PX-18 in the perfusion blood induced a significant 20% reduction in endothelial cell loss compared to veins perfused without PX18, coinciding with significantly reduced sPLA 2 -IIA levels in the media of the vein graft wall. In addition, PX-18 significantly attenuated caspase-3 activation in human umbilical vein endothelial cells subjected to shear stress via mechanical stretch independent of sPLA 2 -IIA. In conclusion, PX-18 protects saphenous vein endothelial cells from arterial blood pressure-induced death, possibly also independent of sPLA 2 -IIA inhibition. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Arterial Blood Pressure Induces Transient C4b-Binding Protein in Human Saphenous Vein Grafts.

    Science.gov (United States)

    Kupreishvili, Koba; Meischl, Christof; Vonk, Alexander B A; Stooker, Wim; Eijsman, Leon; Blom, Anna M; Quax, Paul H A; van Hinsbergh, Victor W M; Niessen, Hans W M; Krijnen, Paul A J

    2017-05-01

    Complement is an important mediator in arterial blood pressure-induced vein graft failure. Previously, we noted activation of cell protective mechanisms in human saphenous veins too. Here we have analyzed whether C4b-binding protein (C4bp), an endogenous complement inhibitor, is present in the vein wall. Human saphenous vein segments obtained from patients undergoing coronary artery bypass grafting (n = 55) were perfused in vitro at arterial blood pressure with either autologous blood for 1, 2, 4, or 6 hr or with autologous blood supplemented with reactive oxygen species scavenger N-acetylcysteine. The segments were subsequently analyzed quantitatively for presence of C4bp and complement activation product C3d using immunohistochemistry. Perfusion induced deposition of C3d and C4bp within the media of the vessel wall, which increased reproducibly and significantly over a period of 4 hr up to 3.8% for C3d and 81% for C4bp of the total vessel area. Remarkably after 6 hr of perfusion, the C3d-positive area decreased significantly to 1.3% and the C4bp-positive area to 19% of the total area of the vein. The areas positive for both C4bp and C3d were increased in the presence of N-acetylcysteine. Exposure to arterial blood pressure leads to a transient presence of C4bp in the vein wall. This may be part of a cell-protective mechanism to counteract arterial blood pressure-induced cellular stress and inflammation in grafted veins. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. In vivo evaluation of femoral blood flow measured with magnetic resonance

    International Nuclear Information System (INIS)

    Henriksen, O.; Staahlberg, F.; Thomsen, C.; Moegelvang, J.; Persson, B.; Lund Univ.

    1989-01-01

    Quantitative measurements of blood flow based on magnetic resonance imaging (MRI) using conventional multiple spin echo sequences were evaluated in vivo in healthy young volunteers. Blood flow was measured using MRI in the femoral vein. The initial slope of the multiple spin echo decay curve, corrected for the T2 decay of non-flowing blood was used to calculate the blood flow. As a reference, the blood flow in the femoral artery was measured simultaneously with an invasive indicator dilution technique. T2 of non-flowing blood was measured in vivo in popliteal veins during regional circulatory arrest. The mean T2 of non-flowing blood was found to be 105±31 ms. The femoral blood flow ranged between 0 and 643 ml/min measured with MRI and between 280 and 531 ml/min measured by the indicator dilution technique. There was thus poor agreement between the two methods. The results indicate that in vivo blood flow measurements made with MRI based on wash-out effects, commonly used in multiple spin echo imaging, do not give reliable absolute values for blood flow in the femoral artery or vein. (orig.)

  16. A Case of Left Renal Vein Ligation in a Patient with Solitary Left Kidney Undergoing Liver Transplantation to Control Splenorenal Shunt and Improve Portal Venous Flow.

    Science.gov (United States)

    Martino, Rodrigo B; Júnior, Eserval Rocha; Manuel, Valdano; Rocha-Santos, Vinicius; D'Albuquerque, Luis Augusto C; Andraus, Wellington

    2017-10-11

    BACKGROUND Adequate portal venous flow is required for successful liver transplantation. Reduced venous flow and blood flow 'steal' by collateral vessels are a concern, and when there is a prominent splenorenal shunt present, ligation of the left renal vein has been recommended to improve portal venous blood flow. CASE REPORT A 51-year-old man who had undergone right nephrectomy in childhood required liver transplantation for liver cirrhosis and hepatocellular carcinoma due to hepatitis C virus (HCV) infection. The patient had no other comorbidity and no history of hepatorenal syndrome. At transplantation surgery, portal venous flow was poor and did not improve with ligation of shunt veins, but ligation of the left renal vein improved portal venous flow. On the first and fifth postoperative days, the patient was treated with basiliximab, a chimeric monoclonal antibody to the IL-2 receptor, and methylprednisolone. The calcineurin inhibitor, tacrolimus, was introduced on the fifth postoperative day. On the sixteenth postoperative day, renal color Doppler ultrasound showed normal left renal parenchyma; hepatic Doppler ultrasound showed good portal vein flow and preserved hepatic parenchyma in the liver transplant. CONCLUSIONS This case report has shown that in a patient with a single left kidney, left renal vein ligation is feasible and safe in a patient with no other risk factors for renal impairment following liver transplantation. Modification of postoperative immunosuppression to avoid calcineurin inhibitors in the very early postoperative phase may be important in promoting good recovery of renal function and to avoid the need for postoperative renal dialysis.

  17. New blood flow radiopharmaceutical

    International Nuclear Information System (INIS)

    Sargent, T. III; Shulgin, A.T.; Mathis, C.A.; Budinger, T.F.

    1983-01-01

    Our program for research into the causes of mental disorders such as schizophrenia, manic depressive illness and senile dementia has led us to the development of a new radiopharmaceutical agent, IDNNA (4-iodo-2,5-dimethoxy-N,N-dimethylamphetamine). A series of some 15 different 131 I labeled molecules with various substitutions on the amine were synthesized and tested, and the uptake of the 131 I labeled conpounds in rats was measured. The dimethyl amine (IDNNA) had the best brain uptake and brain/blood ratio. When injected into a dog and scanned with a whole-body scanner, the uptake in the brain could be clearly seen and quantified. Plasma sampling at the same time showed that the maximum brain/blood ratio of 8.7 occurred at 8 min after injection, and the concentration in brain remained high for at least 15 min. Labeling is achieved by reacting 131 ICl and the precursor, 2,5-dimethoxy-N,N-dimethyl amphetamine, in glacial acetic acid; the reaction is complete in less than one minute

  18. Circadian variation of corticosterone in adrenal vein blood in rats exposed to different light conditions

    International Nuclear Information System (INIS)

    Ostrowska, Z.; Zwirska-Korczala, K.; Buntner, B.; Kos-Kudla, B.

    1993-01-01

    The study was undertaken to examine the regulatory influence of a different light-dark cycle on 24-h rhythm of corticosterone in adrenal vein blood. The present findings suggest that exposure to 'short day' conditions has a suppressive effect on circadian secretion of corticosterone. In rats kept in 'long day' conditions the increase of the mean 24-h corticosterone levels in adrenal vein blood and the acrophase rhythm shift were observed. In rats kept in an inverted illumination cycle the phase reversal in the periodicity of corticosterone was found. (author). 27 refs, 1 fig., 1 tab

  19. Regulation of pulpal blood flow

    International Nuclear Information System (INIS)

    Kim, S.

    1985-01-01

    The regulation of blood flow of the dental pulp was investigated in dogs and rats anesthetized with sodium pentobarbital. Pulpal blood flow was altered by variations of local and systemic hemodynamics. Macrocirculatory blood flow (ml/min/100 g) in the dental pulp was measured with both the 133 Xe washout and the 15-microns radioisotope-labeled microsphere injection methods on the canine teeth of dogs, to provide a comparison of the two methods in the same tooth. Microcirculatory studies were conducted in the rat incisor tooth with microscopic determination of the vascular pattern, RBC velocity, and intravascular volumetric flow distribution. Pulpal resistance vessels have alpha- and beta-adrenergic receptors. Activation of alpha-receptors by intra-arterial injection of norepinephrine (NE) caused both a reduction in macrocirculatory Qp in dogs and decreases in arteriolar and venular diameters and intravascular volumetric flow (Qi) in rats. These responses were blocked by the alpha-antagonist PBZ. Activation of beta-receptors by intra-arterial injection of isoproterenal (ISO) caused a paradoxical reduction of Qp in dogs. In rats, ISO caused a transient increase in arteriolar Qi followed by a flow reduction; arteriolar dilation was accompanied by venular constriction. These macrocirculatory and microcirculatory responses to ISO were blocked by the alpha-antagonist propranolol

  20. Technical note: Measurement of mammary plasma flow in sows by downstream dilution of mammary vein infused para-aminohippuric acid

    DEFF Research Database (Denmark)

    Larsen, Uffe Krogh; Storm, Adam Christian; Theil, Peter Kappel

    2016-01-01

    catheter was surgically implanted in the femoral artery, and another 2 were inserted in the right cranial mammary vein of 8 second- and third-parity sows on d 76 ± 2 SEM of gestation. On the 3rd and 17th days in milk, arterial and venous blood samples were drawn in hourly intervals from 0.5 h before until...... 6.5 h after feeding. The MPF in the right cranial mammary vein was measured by downstream dilution of infused pAH (3.0 mmol/h). Total MPF-pAH was calculated assuming that the measured flow constituted the flow from 5 out of 14 suckled glands on the basis of the anatomical structure of the mammary...

  1. Blood collection from the facial (maxillary)/musculo-cutaneous vein in true frogs (family Ranidae).

    Science.gov (United States)

    Forzán, María J; Vanderstichel, Raphaël V; Ogbuah, Christopher T; Barta, John R; Smith, Todd G

    2012-01-01

    Collection of blood from amphibians, as in other classes of vertebrate animals, is essential to evaluate parameters of health, diagnose hemoparasitism, identify viral and bacterial pathogens, and measure antibodies. Various methods of blood collection have been described for amphibians. Most can be cumbersome (venipucture of femoral vein, ventral abdominal vein or lingual venus plexus) or result in pain or deleterious health consequences (cardiac puncture and toe-clipping). We describe an easy and practical technique to collect blood from frogs and toads that can be used in multiple species and is minimally invasive. The technique consists of puncturing either the facial or, less commonly, the musculo-cutaneous vein and collecting the blood with a capillary tube. These veins run dorsal and parallel to the maxillary bone and can be accessed by quick insertion and withdrawal of a needle through the skin between the upper jawline and the rostral or caudal side of the tympanum. The needle should be of 27 or 30 gauge for anurans weighing more or less than 25 g, respectively. Although the technique has been used by some amphibian researchers for years, it is little known by others and has never been fully described in a peer-reviewed publication.

  2. Autoradiographic study of the regional distribution of gastric blood flow in portal hypertensive rats

    International Nuclear Information System (INIS)

    Geraghty, J.G.; Angerson, W.J.; Carter, D.C.

    1989-01-01

    This study measures regional gastric blood flow in portal hypertensive rats at three separate periods after portal vein ligation using quantitative autoradiography with 14C-labeled iodoantipyrine. The level of corpus mucosal blood flow was significantly reduced in 3-day portal vein-ligated animals compared with sham-operated control animals (30.4 +/- 2.3 vs. 47.1 +/- 5.6 ml/100 g.min). There was no significant difference in corpus mucosal blood flow between portal vein-ligated and sham-operated animals at 7- and 28-day periods, although the level of perfusion was higher in the 28-day portal vein-ligated group. There was no significant difference in antral mucosal or muscle blood flow between portal hypertensive and control animals at any of the study periods. We conclude that the acute period after portal vein ligation is associated with a reduced corpus mucosal microcirculation but that this effect is not sustained in portal hypertensive animals studied at later intervals after portal vein ligation

  3. Cerebral blood-flow tomography

    DEFF Research Database (Denmark)

    Lassen, N A; Henriksen, L; Holm, S

    1983-01-01

    . The Xe-133 flow maps are essentially based on the average Xe-133 concentration over the initial 2 min during and after an inhalation of the inert gas lasting 1 min. These maps agreed very well with the early IMP maps obtained over the initial 10 min following an i.v. bolus injection. The subsequent IMP......, and with low radiation exposure to patient and personnel. On the other hand, IMP gives an image of slightly higher resolution. It also introduces a new class of iodinated brain-seeking compounds allowing, perhaps, imaging of other functions more important than mere blood flow....

  4. Quantification of modulated blood oxygenation levels in single cerebral veins by investigating their MR signal decay

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan [St. Jude Children' s Research Hospital, Memphis, TN (United States). Div. of Translational Imaging Research; University Clinics Jena (Germany). Medical Physics Group; Rauscher, Alexander [University Clinics Jena (Germany). Medical Physics Group; British Columbia Univ., Vancouver (Canada). MRI Research Centre; Reichenbach, Juergen R. [University Clinics Jena (Germany). Medical Physics Group

    2009-07-01

    The transverse magnetization of a single vein and its surrounding tissue is subject to spin dephasing caused by the local magnetic field inhomogeneity which is induced by the very same vessel. This phenomenon can be approximated and simulated by applying the model of an infinitely long and homogeneously magnetized cylinder embedded in a homogeneous tissue background. It is then possible to estimate the oxygenation level of the venous blood by fitting the simulated magnetization-time-course to the measured signal decay. In this work we demonstrate the ability of this approach to quantify the blood oxygenation level (Y) of small cerebral veins in vivo, not only under normal physiologic conditions (Y{sub native}=0.5-0.55) but also during induced changes of physiologic conditions which affect the cerebral venous blood oxygenation level. Changes of blood's oxygenation level induced by carbogen (5% CO{sub 2}, 95% O{sub 2}) and caffeine were observed and quantified, resulting in values of Y{sub carbogen}=0.7 and Y{sub caffeine}=0.42, respectively. The proposed technique may ultimately help to better understand local changes in cerebral physiology during neuronal activation by quantifying blood oxygenation in veins draining active brain areas. It may also be beneficial in clinical applications where it may improve diagnosis of cerebral pathologies as well as monitoring of responses to therapy. (orig.)

  5. Isolation of endothelial colony-forming cells from blood samples collected from the jugular and cephalic veins of healthy adult horses.

    Science.gov (United States)

    Sharpe, Ashley N; Seeto, Wen J; Winter, Randolph L; Zhong, Qiao; Lipke, Elizabeth A; Wooldridge, Anne A

    2016-10-01

    OBJECTIVE To evaluate optimal isolation of endothelial colony-forming cells (ECFCs) from peripheral blood of horses. SAMPLE Jugular and cephalic venous blood samples from 17 adult horses. PROCEDURES Each blood sample was divided; isolation was performed with whole blood adherence (WBA) and density gradient centrifugation (DGC). Isolated cells were characterized by uptake of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate-labeled acetylated low-density lipoprotein (DiI-Ac-LDL), vascular tubule formation, and expression of endothelial (CD34, CD105, vascular endothelial growth factor receptor-2, and von Willebrand factor) and hematopoietic (CD14) cell markers by use of indirect immunofluorescence assay (IFA) and flow cytometry. RESULTS Colonies with cobblestone morphology were isolated from 15 of 17 horses. Blood collected from the cephalic vein yielded colonies significantly more often (14/17 horses) than did blood collected from the jugular vein (8/17 horses). Of 14 cephalic blood samples with colonies, 13 were obtained with DGC and 8 with WBA. Of 8 jugular blood samples with colonies, 8 were obtained with DGC and 4 with WBA. Colony frequency (colonies per milliliter of blood) was significantly higher for cephalic blood samples and samples isolated with DGC. Cells formed vascular tubules, had uptake of DiI-Ac-LDL, and expressed endothelial markers by use of IFA and flow cytometry, which confirmed their identity as ECFCs. CONCLUSIONS AND CLINICAL RELEVANCE Maximum yield of ECFCs was obtained for blood samples collected from both the jugular and cephalic veins and use of DGC to isolate cells. Consistent yield of ECFCs from peripheral blood of horses will enable studies to evaluate diagnostic and therapeutic uses.

  6. Transplacental diffusion and blood flow of gravid bovine uterus

    International Nuclear Information System (INIS)

    Reynolds, L.P.; Ferrell, C.L.; Ford, S.P.

    1985-01-01

    Electromagnetic blood flow transducers and uterine arterial, uterine venous, umbilical venous, fetal femoral arterial, and fetal femoral venous catheters were implanted in 11 cows on day 161 +/- 4 of gestation. Antipyrine (0.66 M) plus NaCl (0.16 M) dissolved in deuterium oxide (D 2 O), or H 2 O, was infused at a constant rate into the fetal femoral vein catheter. Concentrations of antipyrine and D 2 O in uterine arterial and venous blood and antipyrine in fetal arterial and umbilical venous blood, as well as middle uterine arterial blood flow (electromagnetic transducer), were determined. Antipyrine and D 2 O gave similar estimates (steady-state diffusion method) of gravid uterine blood flow. In addition, the slope of the regression of D 2 O on antipyrine estimates was not different from one. Electromagnetic transducers gave estimates of uterine blood flow that were 32-42% of those obtained with steady-state diffusion but were correlated with estimates obtained by use of both antipyrine and D 2 O. The transplacental clearance rate of antipyrine was similar (per kg placenta) to that observed in ewes. It was suggested that the maternal and fetal microvasculatures of the bovine placenta could have a concurrent arrangement with vascular shunts or maldistribution of flows, as has been suggested for the ewe

  7. [THE STATE OF HEPATIC AND SPLANCHNIC BLOOD FLOW IN VARIOUS TYPES OF COMPLICATED PANCREATIC PSEUDOCYSTS].

    Science.gov (United States)

    Kryvoruchko, I A; Goncharova, N M; Andreyeshchev, S A; Yavorska, T P

    2015-05-01

    Investigations were conducted in 37 patients, suffering complicated pancreatic pseudocysts. In accordance to data of ultrasound Doppler flowmetry for the blood flow along portal vein, a. hepatis communis, a. mesenterica superior in complicated pancreatic pseudocysts compensatory--adaptive reactions on level of hepatic--spanchnic blood flow are directed towards restriction of the blood inflow through the portal vein system. This is accompanied by the common peripheral vascular resistence raising in basin of a. mesenterica superior, which have depended upon the patients' state severity, caused by reduction of the volume blood flow in a certan vascular collector. The oxygen debt of the liver in these patients is compensated by the volume blood flow enhancement along a. hepatis communis.

  8. Varicose vein surgery using a pneumatic tourniquet: reduced blood loss and improved cosmesis.

    OpenAIRE

    Thompson, J. F.; Royle, G. T.; Farrands, P. A.; Najmaldin, A.; Clifford, P. C.; Webster, J. H.

    1990-01-01

    A prospective controlled randomised study has been performed of 100 consecutive patients undergoing varicose vein surgery. One group underwent saphenofemoral flush ligation and multiple lower leg avulsions with the leg exsanguinated with a Rhys-Davies cuff, and ischaemia maintained with a pneumatic tourniquet. The other group underwent identical surgery but with a 30 degree head down tilt only. Blood loss was significantly less (13.5 +/- 12 ml vs 133 +/- 78 ml; P less than 0.01) and postopera...

  9. The effects of fenoldopam on coronary conduit blood flow after coronary artery bypass graft surgery.

    LENUS (Irish Health Repository)

    Halpenny, M

    2012-02-03

    OBJECTIVE: To quantify the effects of fenoldopam, 0.1 microg\\/kg\\/min, on left internal mammary artery (LIMA) and saphenous vein blood flow after coronary anastomosis. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: University teaching hospital, single institution. PARTICIPANTS: Thirty-one American Society of Anesthesiologists III patients undergoing elective coronary revascularization. INTERVENTIONS: A perivascular ultrasonic flow probe (Linton Instrumentation, Norfolk, UK) was placed around the LIMA and saphenous vein graft after coronary anastomosis. MEASUREMENTS AND MAIN RESULTS: Immediately before and at 5-minute intervals for 15 minutes after starting the infusion, blood flow was measured in the LIMA and one saphenous vein graft using a transit time ultrasonic flow probe. Heart rate, blood pressure, and central venous pressure were documented at these time points. Administration of fenoldopam, 0.1 microg\\/kg\\/min, did not alter heart rate or blood pressure. A small, nonsignificant increase in LIMA blood flow occurred during the 15-minute study period (30 +\\/- 12 to 35 +\\/- 10 mL\\/min) in patients who received fenoldopam. No significant changes occurred in the placebo group. CONCLUSIONS: The findings indicate that fenoldopam, 0.1 microg\\/kg\\/min, did not influence coronary conduit blood flow to a clinically significant extent. The small increase in LIMA blood flow may be of greater importance in high-risk patients or in the prevention of coronary arterial spasm.

  10. Hepatic blood flow determination. A comparison of 99mTc-diethyl-IDA and indocyanine green as hepatic blood flow indicators in man

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Winkler, K

    1987-01-01

    99mTc-diethyl-acetanilide-iminodiacetic acid (IDA) was compared with indocyanine green (ICG) as an indicator of hepatic blood flow (HBF). Twelve subjects (8 with cirrhosis, 2 with fatty liver, one with pancreatitis, and one with intestinal angina) were studied during hepatic vein catheterization...

  11. Accurate perioperative flow measurement of the portal vein and hepatic and renal artery: A role for preoperative MRI?

    Energy Technology Data Exchange (ETDEWEB)

    Vermeulen, Mechteld A.R., E-mail: mar.vermeulen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Ligthart-Melis, Gerdien C., E-mail: g.ligthart-melis@vumc.nl [Department of Internal Medicine, Dietetics and Nutritional Sciences, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Buijsman, René, E-mail: renebuysman@gmail.com [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Siroen, Michiel P.C., E-mail: m.siroen6@upcmail.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Poll, Marcel C.G. van de, E-mail: mcg.vandepoll@ah.unimaas.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Boelens, Petra G., E-mail: p.boelens@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Dejong, Cornelis H.C., E-mail: chc.dejong@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Schaik, Cors van, E-mail: c.vanschaik@vumc.nl [Department of Radiology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Hofman, Mark B.M., E-mail: mbm.hofman@vumc.nl [Department of Physics and Medical Technology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Leeuwen, Paul A.M. van, E-mail: pam.vleeuwen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands)

    2012-09-15

    Background: Quantification of abdominal blood flow is essential for a variety of gastrointestinal and hepatic topics such as liver transplantation or metabolic flux measurement, but those need to be performed during surgery. It is not clear whether Duplex Doppler Ultrasound during surgery or MRI before surgery is the tool to choose. Objective: To examine whether preoperative evaluation of abdominal blood flow using MRI could prove to be a useful and reliable alternative for the perioperative sonographic approach. Methods: In this study portal and renal venous flow and hepatic arterial flow were sequentially quantified by preoperative MRI, preoperative and perioperative Duplex Doppler Ultrasound (DDUS). 55 Patients scheduled for major abdominal surgery were studied and methods and settings were compared. Additionally, average patient population values were compared. Results: Mean (±SD) plasmaflow measured by perioperative DDUS, preoperative DDUS and MRI, respectively was 433 ± 200/423 ± 162/507 ± 96 ml/min (portal vein); 96 ± 70/74 ± 41/108 ± 91 ml/min (hepatic artery); 248 ± 139/201 ± 118/219 ± 69 ml/min (renal vein). No differences between the different settings of DDUS measurement were detected. Equality of mean was observed for all measurements. Bland Altman Plots showed widespread margins. Hepatic arterial flow measurements correlated with each other, but portal and renal venous flow correlations were absent. Conclusions: Surgery and method (DDUS vs. MRI) do not affect mean flow values. Individual comparison is restricted due to wide range in measurements. Since MRI proves to be more reliable with respect to inter-observer variability, we recommend using mean MRI results in experimental setups.

  12. The design and fabrication of two portal vein flow phantoms by different methods

    Energy Technology Data Exchange (ETDEWEB)

    Yunker, Bryan E., E-mail: bryan.yunker@ucdenver.edu; Lanning, Craig J.; Shandas, Robin; Hunter, Kendall S. [Department of Bioengineering, University of Colorado – Denver/Anschutz, 12700 East 19th Avenue, MS 8607, Aurora, Colorado 80045 (United States); Dodd, Gerald D., E-mail: gerald.dodd@ucdenver.edu; Chang, Samuel; Scherzinger, Ann L. [Department of Radiology, University of Colorado – SOM, 12401 East 17th Avenue, Mail Stop L954, Aurora, Colorado 80045 (United States); Chen, S. James, E-mail: james.chen@ucdenver.edu [Department of Medicine, University of Colorado Denver, Colorado 80045 and Department of Medicine/Cardiology, University of Colorado – SOM, 12401 East 17th Avenue, Mail Stop B132, Aurora, Colorado 80045 (United States); Feng, Yusheng, E-mail: yusheng.feng@utsa.edu [Department of Mechanical Engineering, University of Texas – San Antonio, One UTSA Circle, Mail Stop: AET 2.332, San Antonio, Texas 78249–0670 (United States)

    2014-02-15

    Purpose: This study outlines the design and fabrication techniques for two portal vein flow phantoms. Methods: A materials study was performed as a precursor to this phantom fabrication effort and the desired material properties are restated for continuity. A three-dimensional portal vein pattern was created from the Visual Human database. The portal vein pattern was used to fabricate two flow phantoms by different methods with identical interior surface geometry using computer aided design software tools and rapid prototyping techniques. One portal flow phantom was fabricated within a solid block of clear silicone for use on a table with Ultrasound or within medical imaging systems such as MRI, CT, PET, or SPECT. The other portal flow phantom was fabricated as a thin walled tubular latex structure for use in water tanks with Ultrasound imaging. Both phantoms were evaluated for usability and durability. Results: Both phantoms were fabricated successfully and passed durability criteria for flow testing in the next project phase. Conclusions: The fabrication methods and materials employed for the study yielded durable portal vein phantoms.

  13. Total hepatofugal portal blood flow in cirrhosis demonstrated by transhepatic portography

    Energy Technology Data Exchange (ETDEWEB)

    Burcharth, F; Aagaard, J

    1988-01-01

    We investigated 108 patients with cirrhosis of the liver and portal hypertension by percutaneous transhepatic portography to demonstrate the occurrence and frequency of total hepatofugal portal blood flow. Sixteen patients (14.8%) had a total hepatofugal portal blood flow. The aetiology of portal hypertension and the portal pressure did not differ from that in the group of patients with hepatopetal portal blood flow. A significantly higher percentage of patients in the group with hepatofugal flow had gastro-oesophageal varices (P < 0.025). All patients with varices had bled. Half of the patients in the group with hepatofugal blood flow had a false splenoportographic diagnosis of portal vein thrombosis. In conclusion, total hepatofugal postal blood flow exists more often than hitherto assumed. Hepatofugal blood flow does not relieve portal hypertension nor prevent development of gastro-oesophageal varices or bleeding.

  14. Liver volume, portal vein flow, and clearance of indocyanine green and antipyrine in hyperthyroidism before and after antithyroid treatment

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Sonne, J; Court-Payen, M

    1999-01-01

    The aim of the study was to examine liver volume, portal vein flow, and indocyanine green (ICG) and antipyrine clearance in hyperthyroidism before and after antithyroid drug treatment.......The aim of the study was to examine liver volume, portal vein flow, and indocyanine green (ICG) and antipyrine clearance in hyperthyroidism before and after antithyroid drug treatment....

  15. Evaluation of hepatic blood flow using 99mTc-GSA in rats with hepatic blood flow manipulation

    International Nuclear Information System (INIS)

    Hiraguchi, Etsuo

    1995-01-01

    Blood clearance and hepatic uptake parameters of 99m Tc-DTPA-galactosyl human serum albumin ( 99m Tc-GSA) were evaluated in two groups of rats, normal liver group and CCl 4 induced chronic liver injury group. In each group, four subgroups were classified as follows: simple laparotomy (LAP), hepatic artery ligation (HAL), portal vein ligation (PVL) and both hepatic artery and portal vein ligation (HAL+PVL). 99m Tc-GSA was intravenously injected (50 μg/100 g B.W.) to rats. Heart and liver were targetted as region of interest and time activity curves (TACs) were obtained. The blood clearance parameters (HH4 and Kd) and the hepatic uptake parameters (LHL4 and Ku) were calculated from these TACs. In normal liver group, the mean HH4 of LAP was significantly different from those of PVL and HAL+PVL. Similarly, the other three parameters (LHL4, Kd and Ku) of LAP were significantly different from those of PVL and HAL+PVL. CCl 4 induced chronic liver injury group showed significant difference on all four parameters in four subgroups. Hepatic tissue blood flow rates (HTBFR) calculated by Laser Doppler flowmeter correlated well with 99m Tc-GSA parameters in both groups. These results suggest that 99m Tc-GSA is useful to estimate hepatic blood flow not only in rats with normal liver, but also in rats with CCl 4 induced chronic liver injury. (author)

  16. The blood flow changes associated with idiopathic and secondary intracranial hypertension

    International Nuclear Information System (INIS)

    Bateman, G.

    2002-01-01

    Full text: The radiological diagnosis of idiopathic intracranial hypertension (IIH) is one of exclusion and as the MR venogram is prone to flow artefacts, the diagnosis of secondary intracranial hypertension (SIH) can also be problematic. The purpose of this paper is to define the blood flow characteristics, which are useful in the diagnosis of these conditions. Twelve patients with clinical findings suggestive of IIH and 12 control subjects were investigated with MR venography and MR flow quantification studies of the cerebral arteries and veins. Total cerebral blood flow, superior sagittal sinus (SSS) and straight sinus (ST) blood flows were measured. MR venography confirmed 7 of the 12 patients had venous outflow obstruction and thus SIH. The remaining 5 patients had IIH. The control patients mean total blood flow was 855 ml/min, the SSS flow was 400ml/min and the ST flow 117 ml/min. The total blood flow in the IIH patients was 46% higher (P = 0.0002) and the ST blood flow 38% higher (P = 0.05) than the control group, the SSS flow was 17% higher but this failed to reach significance. In SIH the SSS flow was reduced by 25% (P = 0.003) compared with the control group, the total and ST blood flow were not significantly altered. In IIH there is hyperaemia and the SSS appears limited in its ability to increase flow, therefore venous collaterals carry a greater load. In SIH, selective obstruction of the SSS reduces flow in this vessel but total blood flow is normal indicating there is also increased flow in collateral veins. Presumably the limited ability of the SSS to drain blood away from the brain in each condition raises venous sinus pressure and alters CSF resorption giving raised CSF pressure. Copyright (2002) Blackwell Science Pty Ltd

  17. Cutaneous blood flow in psoriasis

    International Nuclear Information System (INIS)

    Klemp, P.; Staberg, B.

    1983-01-01

    The disappearance rate of 133 Xe was studied in 20 patients with psoriasis vulgaris, using an epicutaneous labeling technique in involved skin lesions or normal-appearing skin of the proximal extensor site of the forearm. Control experiments were performed in 10 normal subjects. Calculations of the cutaneous blood flow (CBF) in psoriatic skin lesions were performed using a tissue-to-blood partition coefficient for 133 Xe, lambda c,pso, of 1.2 ml/100 g/min. lambda c,pso was estimated after the relative content of water, lipids, and proteins had been analyzed in psoriatic skin biopsies of 6 patients with untreated psoriasis. The mean relative content of water was markedly reduced to 23.5 +/- 1.5% (SEM), and lipids and proteins were markedly increased to 2.5 +/- 0.7% and 74.0 +/- 2.2, respectively, compared to previously published data for normal skin (water 72.5%, lipids 1%, proteins 26.5%). Mean CBF in untreated psoriatic skin was 63.5 +/- 9.0 ml/100 g/min. This was significantly higher than the mean CBF in 10 normal subjects, 6.3 +/- 0.5 ml/100 g/min (p much less than 0.0001). Mean CBF in normal-appearing skin in patients with psoriasis was 11.0 +/- 1.3 ml/100 g/min. This was significantly higher than CBF in normal subjects (p less than 0.0002)

  18. Microsphere estimates of blood flow: Methodological considerations

    International Nuclear Information System (INIS)

    von Ritter, C.; Hinder, R.A.; Womack, W.; Bauerfeind, P.; Fimmel, C.J.; Kvietys, P.R.; Granger, D.N.; Blum, A.L.

    1988-01-01

    The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 x 10 6 microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period

  19. Blood cell interactions and segregation in flow.

    Science.gov (United States)

    Munn, Lance L; Dupin, Michael M

    2008-04-01

    For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allowing blood to perform a variety of critical functions. Our current understanding of these unusual flow properties of blood have been made possible by the ingenuity and diligence of a number of researchers, including Harry Goldsmith, who developed novel technologies to visualize and quantify the flow of blood at the level of individual cells. Here we summarize efforts in our lab to continue this tradition and to further our understanding of how blood cells interact with each other and with the blood vessel wall.

  20. Chronic intestinal ischemia and splanchnic blood-flow

    DEFF Research Database (Denmark)

    Zacho, Helle Damgaard; Henriksen, Jens Henrik; Abrahamsen, Jan

    2013-01-01

    AIM: To determine the splanchnic blood flow and oxygen uptake in healthy-subjects and patients and to relate the findings to body-composition. METHODS: The total splanchnic blood flow (SBF) and oxygen uptake (SO₂U) were measured in 20 healthy volunteers (10 women) and 29 patients with suspected...... arteries was performed during the same investigation. A whole-body dual-energy x-ray absorptiometry scan was performed in healthy volunteers to determine body composition. RESULTS: Angiography revealed no atherosclerotic lesions in the intestinal arteries. The mean baseline SBF was 1087 mL/min (731...... chronic intestinal ischemia (15 women), age 40-85 years, prior to and after a standard meal. The method is based on the Fick principle using the continuous infusion of an indicator (99mTechnetium-labelled mebrofenin) and catheterization of an artery and the hepatic vein. An angiography of the intestinal...

  1. Blood flow and blood volume in a transplanted rat fibrosarcoma

    International Nuclear Information System (INIS)

    Tozer, G.M.; Morris, C.C.

    1990-01-01

    Blood flow measurements following i.v. infusion of iodi-antipyrine labelled with 14 C ( 14 C-IAP) and blood volume measurements following i.v. injection of 125 I human serum albumin and 51 Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14 C-IAP w as found to be 0.79 ± 0.07 which is similar to most of the normal tissues studied. The solubility of 14 C-IAP in plasma was found to be higher than that in whole blood. Blood flow to tumours 3 was found to be 17.9 ± 4.0 ml blood 100 g tissue -1 xmin -1 . These values were considered to be primarily measurements of nutritive flow. Blood in the tumours was found to occupy around 1% of the tissue space which was similar to that found for normal muscle and skin. There was no direct correlation between % blood volume and blood flow for the different tissues studied. Th haematocrit of blood contained in tumour tissue was calculated to be significantly lower than that of blood contained in the normal tissues. It was suspected that permeability of tumour blood vessel walls to 125 I-HSA could have accounted for this difference. (author). 41 refs.; 2 figs.; 3 tabs

  2. Regional cerebral blood flow in schizophrenia

    International Nuclear Information System (INIS)

    Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

    1982-01-01

    Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions

  3. Regional cerebral blood flow in schizophrenia

    Energy Technology Data Exchange (ETDEWEB)

    Mathew, R.J.; Duncan, G.C.; Weinman, M.L.; Barr, D.L.

    1982-10-01

    Regional cerebral blood flow (rCBF) was measured via xenon133 inhalation technique in 23 patients with schizophrenia and 18 age- and sex-matched controls. The mean blood flow to both hemispheres was found to be lower for the patients. The patients and their controls did not differ on interhemispheric differences in blood flow. There were no differences in rCBF between medicated and unmedicated, subchronic and chronic, and paranoid and nonparanoid patients. Hallucinations were associated with reduced blood flow to several postcentral regions.

  4. Measurement of Finger Blood Flow in Raynauds Phenomenon by Radionuclide Angiography

    International Nuclear Information System (INIS)

    Lim, Sang Moo; Chung, June Key; Lee, Myung Chul; Kim, Sang Joon; Choi, Sung Jae; Koh, Chang Soon

    1987-01-01

    In Raynauds phenomenon, the authors measured finger blood flow after ice water exposure by analyzing the time activity curve of radionuclide angiography on both hands. The results were as follows: 1) The digital blood flow did not decrease after ice water exposure in normal subjects. 2) In the patients with Raynauds phenomenon, there were two groups: the one had decreased digital blood flow after cold exposure, and the other had paradoxically increased digital blood flow after cold exposure. 3) There was no difference in the digital blood flow of hand in room temperature between the normal and the patients with reduced digital blood flow after cold exposure, but the digital blood flow of the hand in room temperature was markedly reduced in the patients with paradoxically increased flow after cold exposure. 4) In the static image the difference was not significant in comparison with the dynamic study, because it represents pooling of the blood in the vein rather than flow. 5) After the treatment with nifedipine, the digital blood flow increased. In conclusion, the radionuclide angiography was useful in measuring the digital blood flow in Raynauds phenomenon, and further studies with various drugs is expected.

  5. Cerebral blood flow and metabolism during exercise: implications for fatigue

    DEFF Research Database (Denmark)

    Seifert, T.; Lieshout, J.J. van; Secher, Niels

    2008-01-01

    During exercise: the Kety-Schmidt-determined cerebral blood flow (CBF) does not change because the jugular vein is collapsed in the upright position. In contrast, when CBF is evaluated by (133)Xe clearance, by flow in the internal carotid artery, or by flow velocity in basal cerebral arteries......, a approximately 25% increase is detected with a parallel increase in metabolism. During activation, an increase in cerebral O(2) supply is required because there is no capillary recruitment within the brain and increased metabolism becomes dependent on an enhanced gradient for oxygen diffusion. During maximal...... whole body exercise, however, cerebral oxygenation decreases because of eventual arterial desaturation and marked hyperventilation-related hypocapnia of consequence for CBF. Reduced cerebral oxygenation affects recruitment of motor units, and supplemental O(2) enhances cerebral oxygenation and work...

  6. Vascular structure determines pulmonary blood flow distribution

    Science.gov (United States)

    Hlastala, M. P.; Glenny, R. W.

    1999-01-01

    Scientific knowledge develops through the evolution of new concepts. This process is usually driven by new methodologies that provide observations not previously available. Understanding of pulmonary blood flow determinants advanced significantly in the 1960s and is now changing rapidly again, because of increased spatial resolution of regional pulmonary blood flow measurements.

  7. Coupling between arterial and venous cerebral blood flow during postural change

    DEFF Research Database (Denmark)

    Ogoh, Shigehiko; Washio, Takuro; Sasaki, Hiroyuki

    2016-01-01

    In supine humans the main drainage from the brain is through the internal jugular vein (IJV) but the vertebral veins (VV) become important during orthostatic stress because the IJV is partially collapsed. To identify the effect of this shift in venous drainage from the brain on the cerebral...... blood flow (r=0.649, P=0.004) and the two flows were coupled during manipulation of the end-tidal CO2 tension (supine, r=0.551, P=0.004; seated, r=0.612, P

  8. Global and regional brain atrophy is associated with low or retrograde facial vein flow in multiple sclerosis

    Directory of Open Access Journals (Sweden)

    Dejan Jakimovski

    2017-09-01

    Full Text Available Increased collateral facial vein (FV flow may be associated with structural damage in patients with multiple sclerosis (MS. The objective was to assess differences in FV flow and magnetic resonance imaging (MRI-derived outcomes in MS. The study included 136 MS patients who underwent neck and head vascular system examination by echo-color Doppler. Inflammatory MRI markers were assessed on a 3T MRI using a semi-automated edge detection and contouring/ thresholding technique. MRI volumetric outcomes of whole brain (WB, gray matter (GM, white matter (WM, cortex, ventricular cerebrospinal fluid (vCSF, deep gray matter (DGM, thalamus, caudate nucleus (CN, putamen, globus pallidus (GP, and hippocampus were calculated. Independent t-test and ANCOVA, adjusted for age, were used to compare groups based on FV flow quartiles. Thirty-four MS patients with FV flow ≤327.8 mL/min (lowest quartile had significantly lower WB (P327.8 mL/min (higher quartiles. There were no differences in T1-, T2- and gadolinium- enhancing lesion volumes between the quartile groups. The lack of an association between FV blood flow and inflammatory MRI measures in MS patients, but an association with brain atrophy, suggests that the severity of neurodegenerative process may be related to hemodynamic alterations. MS patients with more advanced global and regional brain atrophy showed low or retrograde FV volume flow.

  9. Bone blood flow and metabolism in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Kemppainen, Jukka; Kaskinoro, Kimmo

    2012-01-01

    Human bone blood flow and metabolism during physical exercise remains poorly characterised. In the present study we measured femoral bone blood flow and glucose uptake in young healthy subjects by positron emission tomography in three separate protocols. In six women, blood flow was measured...... in femoral bone at rest and during one leg intermittent isometric exercise with increasing exercise intensities. In nine men, blood flow in femur was determined at rest and during dynamic one leg exercise, and two other physiological perturbations: moderate systemic hypoxia (14 O(2) ) at rest and during...... exercise, and during intra-femoral infusion of high-dose adenosine. Bone glucose uptake was measured at rest and during dynamic one leg exercise in five men. The results indicate that isometric exercise increased femoral bone blood flow from rest (1.8 ± 0.6 ml/100g/min) to low intensity exercise (4.1 ± 1...

  10. The Physics of Coronary Blood Flow

    CERN Document Server

    Zamir, M

    2005-01-01

    Coronary blood flow is blood flow to the heart for its own metabolic needs. In the most common form of heart disease there is a disruption in this flow because of obstructive disease in the vessels that carry the flow. The subject of coronary blood flow is therefore associated mostly with the pathophysiology of this disease, rarely with dynamics or physics. Yet, the system responsible for coronary blood flow, namely the "coronary circulation," is a highly sophisticated dynamical system in which the dynamics and physics of the flow are as important as the integrity of the conducting vessels. While an obstruction in the conducting vessels is a fairly obvious and clearly visible cause of disruption in coronary blood flow, any discord in the complex dynamics of the system can cause an equally grave, though less conspicuous, disruption in the flow. This book is devoted specifically to the dynamics and physics of coronary blood flow. While relevance to the clinical and pathophysiological issues is clearly maintaine...

  11. Subcutaneous blood flow in psoriasis

    International Nuclear Information System (INIS)

    Klemp, P.

    1985-01-01

    The simultaneously recorded disappearance rates of 133 xe from subcutaneous adipose tissue in the crus were studied in 10 patients with psoriasis vulgaris using atraumatic labeling of the tissue in lesional skin (LS) areas and symmetrical, nonlesional skin (NLS) areas. Control experiments were performed bilaterally in 10 younger, healthy subjects. The subcutaneous washout rate constant was significantly higher in LS, 0.79 +/- 0.05 min-1 x 10(2) compared to the washout rate constant of NLS, 0.56 +/- 0.07 min-1. 10(2), or the washout rate constant in the normal subjects, 0.46 +/- 0.17 min-1 x 10(2). The mean washout rate constant in NLS was 25% higher than the mean washout rate constant in the normal subjects. The difference was, however, not statistically significant. Differences in the washout rate constants might be due to abnormal subcutaneous tissue-to-blood partition (lambda) in the LS--and therefore not reflecting the real differences in the subcutaneous blood flow (SBF). The lambda for 133 Xe was therefore measured--using a double isotope washout method ( 133 Xe and [ 131 I]antipyrine)--in symmetrical sites of the lateral crus in LS and NLS of 10 patients with psoriasis vulgaris and in 10 legs of normal subjects. In LS the lambda was 4.52 +/- 1.67 ml/g, which was not statistically different from that of NLS, 5.25 +/- 2.19 ml/g, nor from that of normal subcutaneous tissue, 4.98 +/- 1.04 ml/g. Calculations of the SBF using the obtained lambda values gave a significantly higher SBF in LS, 3.57 +/- 0.23 ml/100 g/min, compared to SBF in the NLS, 2.94 +/- 0.37 ml/100 g/min. There was no statistically significant difference between SBF in NLS and SBF in the normal subjects. The increased SBF in LS of psoriatics might be a secondary phenomenon to an increased heat loss in the lesional skin

  12. Study of the portal blood flow by gamma-scintigraphy in rectal administration of 133Xe solution

    International Nuclear Information System (INIS)

    Vorontsov, Yu.P.; Dmitrievnkov, B.N.; Andronov, S.V.; Alferov, G.A.

    1981-01-01

    Data on 133 Xe running through the liver during the administration of its solutions rectally (intraintestinally) and directly into the system of the portal vein (into one of the mesenteric veins) have been correlated in experiment on 12 rabbits. Good correlation of the mean of 133 Xe (passing has been shown for both methods of the portal blood flow study). A possibility to study the hepatic blood flow on the basis of clinical results using rectal administration of 133 Xe solution is discussed. The authors discuss the mechanism of 133 Xe penetration from the solution into the blood through the rectal wall

  13. Blood Cell Interactions and Segregation in Flow

    OpenAIRE

    Munn, Lance L.; Dupin, Michael M.

    2008-01-01

    For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allo...

  14. Sequential topographical portrayal of myocardial blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Richeson, J.F.; Waag, R.C.; Zwierzynski, D.; Schenk, E.A. (Univ. of Rochester School of Medicine and Dentistry, NY (USA))

    1989-08-01

    Methods to portray myocardial blood flow in a two-dimensional continuum are advantageous in that they allow blood flow history to be overlaid on histological or histochemical descriptions of the consequences of ischemia. We describe here autoradiographic methods that allow such portrayals at three separate times during the evolution of ischemic injury. A computer-based image-analysis system was used to derive such flow maps by taking advantage of the physical characteristics of radioactive isotopes.

  15. Radioisotopic flow scanning for portal blood flow and portal hypertension

    International Nuclear Information System (INIS)

    Hesdorffer, C.S.; Bezwoda, W.R.; Danilewitz, M.D.; Esser, J.D.; Tobias, M.

    1987-01-01

    The use of a simple, noninvasive, isotope scanning technique for the determination of relative portal blood flow and detection of portal hypertension is described. Using this technique the presence of portal hypertension was demonstrated in seven of nine patients known to have elevated portal venous pressure. By contrast, esophageal varices were demonstrated in only five of these patients, illustrating the potential value of the method. Furthermore, this technique has been adapted to the study of portal blood flow in patients with myeloproliferative disorders with splenomegaly but without disturbances in hepatic architecture. Results demonstrate that the high relative splenic flow resulting from the presence of splenomegaly may in turn be associated with elevated relative portal blood flow and portal hypertension. The theoretic reasons for the development of flow-related portal hypertension and its relationship to splenic blood flow are discussed

  16. Blood in the gastric lumen increases splanchnic blood flow and portal pressure in portal-hypertensive rats.

    Science.gov (United States)

    Chen, L; Groszmann, R J

    1996-10-01

    In portal-hypertensive humans, portal blood flow and pressure increase after a meal. These hemodynamic changes may increase variceal rupture risk. The aim of this study was to determine whether blood in the stomach lumen increases splanchnic flow and portal pressure (PP) in portal-hypertensive rats. superior mesenteric artery flow and PP were measured in conscious, unrestrained, fasted partial portal vein-ligated rats with chronically implanted Doppler flow probes or portal vein catheters before and after gavage with heparinized, warmed blood from donor rats, air, standard meal, or empty tube. Percentage of changes in flow and pressure from baseline were significantly greater after gavage with blood (an increase of 22.6% +/- 3.5% and an increase of 16.4% +/- 3.1%, respectively) than empty tube (an increase of 3.4% +/- 0.6% and a decrease of 5.4% +/- 3.5%, respectively) (P empty tube (P calories probably contributes to these hemodynamic changes. In patients with variceal hemorrhage, blood in the stomach may increase the risk of persistent variceal bleeding or rebleeding.

  17. Blood flow autoregulation in pedicled flaps

    DEFF Research Database (Denmark)

    Bonde, Christian T; Holstein-Rathlou, Niels-Henrik; Elberg, Jens J

    2009-01-01

    was to evaluate if, and to what extent, a tissue flap could compensate a reduction in blood flow due to an acute constriction of the feed artery. Further, we wanted to examine the possible role of smooth muscle L-type calcium channels in the autoregulatory mechanism by pharmacological intervention with the L......, the flow in the pedicle was reduced and the flow was recorded. RESULTS: The flaps showed a strong autoregulatory response with complete compensation for flow reductions of up to 70-80%. Infusion of nimodipine caused a 28+/-10% increase in blood flow and removed the autoregulation. Papaverine caused...... a further increase in blood flow by 61+/-19%. The time control experiments proved that the experimental procedure was reproducible and stable over time. CONCLUSIONS: A tissue flap can nearly completely compensate for repeated flow reductions of up to 70-80%. This is due to a decrease in the peripheral...

  18. Quantitative blood flow analysis with digital techniques

    International Nuclear Information System (INIS)

    Forbes, G.

    1984-01-01

    The general principles of digital techniques in quantitating absolute blood flow during arteriography are described. Results are presented for a phantom constructed to correlate digitally calculated absolute flow with direct flow measurements. The clinical use of digital techniques in cerebrovascular angiography is briefly described. (U.K.)

  19. Arteriovenous oscillations of the redox potential: Is the redox state influencing blood flow?

    Science.gov (United States)

    Poznanski, Jaroslaw; Szczesny, Pawel; Pawlinski, Bartosz; Mazurek, Tomasz; Zielenkiewicz, Piotr; Gajewski, Zdzislaw; Paczek, Leszek

    2017-09-01

    Studies on the regulation of human blood flow revealed several modes of oscillations with frequencies ranging from 0.005 to 1 Hz. Several mechanisms were proposed that might influence these oscillations, such as the activity of vascular endothelium, the neurogenic activity of vessel wall, the intrinsic activity of vascular smooth muscle, respiration, and heartbeat. These studies relied typically on non-invasive techniques, for example, laser Doppler flowmetry. Oscillations of biochemical markers were rarely coupled to blood flow. The redox potential difference between the artery and the vein was measured by platinum electrodes placed in the parallel homonymous femoral artery and the femoral vein of ventilated anesthetized pigs. Continuous measurement at 5 Hz sampling rate using a digital nanovoltmeter revealed fluctuating signals with three basic modes of oscillations: ∼ 1, ∼ 0.1 and ∼ 0.01 Hz. These signals clearly overlap with reported modes of oscillations in blood flow, suggesting coupling of the redox potential and blood flow. The amplitude of the oscillations associated with heart action was significantly smaller than for the other two modes, despite the fact that heart action has the greatest influence on blood flow. This finding suggests that redox potential in blood might be not a derivative but either a mediator or an effector of the blood flow control system.

  20. Peak-counts blood flow model-errors and limitations

    International Nuclear Information System (INIS)

    Mullani, N.A.; Marani, S.K.; Ekas, R.D.; Gould, K.L.

    1984-01-01

    The peak-counts model has several advantages, but its use may be limited due to the condition that the venous egress may not be negligible at the time of peak-counts. Consequently, blood flow measurements by the peak-counts model will depend on the bolus size, bolus duration, and the minimum transit time of the bolus through the region of interest. The effect of bolus size on the measurement of extraction fraction and blood flow was evaluated by injecting 1 to 30ml of rubidium chloride in the femoral vein of a dog and measuring the myocardial activity with a beta probe over the heart. Regional blood flow measurements were not found to vary with bolus sizes up to 30ml. The effect of bolus duration was studied by injecting a 10cc bolus of tracer at different speeds in the femoral vein of a dog. All intravenous injections undergo a broadening of the bolus duration due to the transit time of the tracer through the lungs and the heart. This transit time was found to range from 4-6 second FWHM and dominates the duration of the bolus to the myocardium for up to 3 second injections. A computer simulation has been carried out in which the different parameters of delay time, extraction fraction, and bolus duration can be changed to assess the errors in the peak-counts model. The results of the simulations show that the error will be greatest for short transit time delays and for low extraction fractions

  1. Postradiation regional cerebral blood flow in primates

    International Nuclear Information System (INIS)

    Cockerham, L.G.; Cerveny, T.J.; Hampton, J.D.

    1986-01-01

    Early transient incapacitation (ETI) is the complete cessation of performance during the first 30 min after radiation exposure and performance decrement (PD) is a reduction in performance at the same time. Supralethal doses of radiation have been shown to produce a marked decrease in regional cerebral blood flow in primates concurrent with hypotension and a dramatic release of mast cell histamine. In an attempt to elucidate mechanisms underlying the radiation-induced ETI/PD phenomenon and the postradiation decrease in cerebral blood flow, primates were exposed to 100 Gy (1 Gy = 100 rads), whole-body, gamma radiation. Pontine and cortical blood flows were measured by hydrogen clearance, before and after radiation exposure. Systemic blood pressures were determined simultaneously. Systemic arterial histamine levels were determined preradiation and postradiation. Data obtained indicated that radiated animals showed a decrease in blood flow of 63% in the motor cortex and 51% in the pons by 10 min postradiation. Regional cerebral blood flow of radiated animals showed a slight recovery 20 min postradiation, followed by a fall to the 10 min nadir by 60 min postradiation. Immediately, postradiation systemic blood pressure fell 67% and remained at that level for the remainder of the experiment. Histamine levels in the radiated animals increased a hundredfold 2 min postradiation. This study indicates that regional cerebral blood flow decreases postradiation with the development of hypotension and may be associated temporally with the postradiation release of histamine

  2. Fast Blood Vector Velocity Imaging using ultrasound: In-vivo examples of complex blood flow in the vascular system

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Lindskov; Udesen, Jesper; Gran, Fredrik

    2008-01-01

    Conventional ultrasound methods for acquiring color flow images of the blood motion are restricted by a relatively low frame rate and angle dependent velocity estimates. The Plane Wave Excitation (PWE) method has been proposed to solve these limitations. The frame rate can be increased, and the 2-D...... vector velocity of the blood motion can be estimated. The transmitted pulse is not focused, and a full speckle image of the blood can be acquired for each emission. A 13 bit Barker code is transmitted simultaneously from each transducer element. The 2-D vector velocity of the blood is found using 2-D...... speckle tracking between segments in consecutive speckle images. The flow patterns of six bifurcations and two veins were investigated in-vivo. It was shown: 1) that a stable vortex in the carotid bulb was present opposed to other examined bifurcations, 2) that retrograde flow was present...

  3. Blood flow determinations utilizing digital densitometry

    International Nuclear Information System (INIS)

    Lois, F.; Mankovich, N.J.; Gomes, A.S.

    1987-01-01

    A method of obtaining relative and absolute blood flow measurements from digital densitometry was evaluated with a simulated vessel phantom and a hydrodynamic model. A digital vascular imaging system capable of acquisition in 512 2 and 1024 2 mode was used. Relative and absolute blood flow were measured using parameters derived from the densitometric curve. Since application of densitometric data to absolute flow measurements requires the vessel diameter, an algorithm for vessel size determination was created. Gray scale changes were demonstrated to be linearly related to contrast concentration. The variance of vessel size determination was significantly different in all combinations of 1024 2 and 512 2 imaging with 15 cm or 35 cm field size. The error in vessel size determination was significantly less using the larger 1024 2 matrix and the smaller 15 cm image intensifier field size, as shown by the smaller variance. In relative flow determinations, there was good correlation between the flow and four parameters of the densitometric curve with no significant differences between 512 2 and 1024 2 imaging. Absolute flow determinations had slightly lower correlation to actual flow but were not significantly different from relative flow determinations. Relative and absolute blood flow determinations can be performed adequately with either 512 2 or 1024 2 imaging. The increased accuracy in vessel size determination with 1024 2 imaging makes this high resolution system potentially perferable to determine absolute blood flow. (orig.)

  4. Blood Clotting and Pregnancy

    Medline Plus

    Full Text Available ... clot. Blood clots in pregnant women tend to form in the deep veins of the legs or ... potentially dangerous to your baby. Blood clots can form inside the placenta, cutting off blood flow and ...

  5. [The comparison of blood levels between peripheral vein and tooth extraction wound after the oral administration of antibiotics (author's transl)].

    Science.gov (United States)

    Hashimoto, T; Ookawa, H; Morishita, M; Takeyasu, K; Shiiki, K; Imoto, T

    1981-06-01

    The oral administration of 300 mg of clindamycin was undertaken on 23 patients, of 500 mg of cefadroxil on 11 patients and of 250 mg of talampicillin on 12 patients, and then tooth extraction was performed under local anesthesia. Blood samples were taken from the extraction wound and the peripheral vein at the same time and assayed by the bioassay method. The blood levels of clindamycin and cefadroxil indicated a similar pattern between the extraction wound and the peripheral vein, but the blood level of talampicillin reached peek level rapider than clindamycin and cefadroxil. The blood levels of the extraction wound were 60 - 80% as compared with the venous blood levels with each antimicrobial agent.

  6. Brachial blood flow under relative levels of blood flow restriction is decreased in a nonlinear fashion.

    Science.gov (United States)

    Mouser, J Grant; Ade, Carl J; Black, Christopher D; Bemben, Debra A; Bemben, Michael G

    2018-05-01

    Blood flow restriction (BFR), the application of external pressure to occlude venous return and restrict arterial inflow, has been shown to increase muscular size and strength when combined with low-load resistance exercise. BFR in the research setting uses a wide range of pressures, applying a pressure based upon an individual's systolic pressure or a percentage of occlusion pressure; not a directly determined reduction in blood flow. The relationship between relative pressure and blood flow has not been established. To measure blood flow in the arm under relative levels of BFR. Forty-five people (18-40 years old) participated. Arterial occlusion pressure in the right arm was measured using a 5-cm pneumatic cuff. Blood flow in the brachial artery was measured at rest and at pressures between 10% and 90% of occlusion using ultrasound. Blood flow decreased in a nonlinear, stepped fashion. Blood flow decreased at 10% of occlusion and remained constant until decreasing again at 40%, where it remained until 90% of occlusion. The decrease in brachial blood flow is not proportional to the applied relative pressure. The prescription of blood flow restriction should take into account the stimulus provided at each relative level of blood flow. © 2017 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  7. Direct and indirect assessment of skeletal muscle blood flow in chronic congestive heart failure

    International Nuclear Information System (INIS)

    LeJemtel, T.H.; Scortichini, D.; Katz, S.

    1988-01-01

    In patients with chronic congestive heart failure (CHF), skeletal muscle blood flow can be measured directly by the continuous thermodilution technique and by the xenon-133 clearance method. The continuous thermodilution technique requires retrograde catheterization of the femoral vein and, thus, cannot be repeated conveniently in patients during evaluation of pharmacologic interventions. The xenon-133 clearance, which requires only an intramuscular injection, allows repeated determination of skeletal muscle blood flow. In patients with severe CHF, a fixed capacity of the skeletal muscle vasculature to dilate appears to limit maximal exercise performance. Moreover, the changes in peak skeletal muscle blood flow noted during long-term administration of captopril, an angiotensin-converting enzyme inhibitor, appears to correlate with the changes in aerobic capacity. In patients with CHF, resting supine deep femoral vein oxygen content can be used as an indirect measurement of resting skeletal muscle blood flow. The absence of a steady state complicates the determination of peak skeletal muscle blood flow reached during graded bicycle or treadmill exercise in patients with chronic CHF. Indirect assessments of skeletal muscle blood flow and metabolism during exercise performed at submaximal work loads are currently developed in patients with chronic CHF

  8. Frequency encoding in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, D.J.; Sosnovtseva, Olga; Pavlov, A.N.

    2005-01-01

    With a model of renal blood flow regulation, we examined consequences of tubuloglomerular feedback (TGF) coupling to the myogenic mechanism via voltage-gated Ca channels. The model reproduces the characteristic oscillations of the two mechanisms and predicts frequency and amplitude modulation...... of the myogenic oscillation by TGF. Analysis by wavelet transforms of single-nephron blood flow confirms that both amplitude and frequency of the myogenic oscillation are modulated by TGF. We developed a double-wavelet transform technique to estimate modulation frequency. Median value of the ratio of modulation...... TGF cycle to the next. We used a blood pressure signal recorded by telemetry from a conscious rat as the input to the model. Blood pressure fluctuations induced variability in the modulation records similar to those found in the nephron blood flow results. Frequency and amplitude modulation can...

  9. Measurement of bone blood flow in sheep

    International Nuclear Information System (INIS)

    Rosenthal, M.S.; Lehner, C.E.; Pearson, D.W.; Kanikula, T.; Adler, G.; Venci, R.; Lanphier, E.H.; DeLuca, P.M. Jr.

    1984-01-01

    Bone blood flow in sheep tibia has been estimated via the measurement of the perfusion limited clearance of 41 Ar from the bone mineral matrix following fast neutron activation of 44 Ca. Tibia blood flows were estimated for the intact sheep, and after the installation of an intramedullary pressure tap to elevate bone marrow pressure by saline infusion. The results indicate that normal blood flow in the tibia is in the range of 1.1 to 3.7 ml/100ml-min in the intact animal and at normal marrow pressure. With an elevated intramedullary pressure of approximately 100 mmHg, the bone blood flow measured varied around 0.5 to 1.1 ml/100ml-min. 12 refs., 5 figs., 1 tab

  10. Determination of myocardial blood flow by videodensitometry

    International Nuclear Information System (INIS)

    Erikson, U.; Helmius, G.; Hennig, K.; Johansson, L.; Enghoff, E.; Ruhn, G.

    1981-01-01

    Videodensitometry has hitherto been used as a tool for measuring regional blood flow in the kidneys and lungs by means of the well known Stewart Hamilton curve (wash-out) technique. This preliminary report suggests the possibility of using this method to measure coronary blood flow. Thirty-six patients, 29 of whom had angina pectoris, underwent videodensitometry in connection with coronary angiography. (orig.) [de

  11. Nutrient and nonnutrient renal blood flow

    International Nuclear Information System (INIS)

    Young, J.S.; Passmore, J.C.; Hartupee, D.A.; Baker, C.H.

    1990-01-01

    The role of prostaglandins in the distribution of total renal blood flow (TRBF) between nutrient and nonnutrient compartments was investigated in anesthetized mongrel dogs. Renal blood flow distribution was assessed by the xenon 133 freeze-dissection technique and by rubidium 86 extraction after ibuprofen treatment. Ibuprofen (13 mg/kg) significantly decreased TRBF by 16.3% +/- 1.2% (mean +/- SEM electromagnetic flow probe; p less than 0.005), but did not alter blood flows to the outer cortex (3.7 vs 4.3 ml/min per gram), the inner cortex (2.6 vs 2.7 ml/min per gram), and the other medulla (1.5 vs 1.5 ml/min per gram), which suggests a decrease in nonnutrient flow. In a separate group of animals the effect of reduced blood flow on the nutrient and nonnutrient components was determined by mechanically reducing renal arterial blood flow by 48%. Unlike the ibuprofen group, nutrient blood flows were proportionally reduced with the mechanical decrease in TRBF in the outer cortex (1.9 ml/min per gram, p less than 0.05), the inner cortex (1.4 ml/min per gram, p less than 0.05), and the outer medulla (0.8 ml/min per gram, p less than 0.01). These results indicate no shift between nutrient and nonnutrient compartments. Nutrient and nonnutrient renal blood flows of the left kidney were also determined by 86Rb extraction. After ibuprofen treatment, nonextracted 86Rb decreased to 12.1% from the control value of 15.6% (p less than 0.05). Mechanical reduction of TRBF did not significantly decrease the proportion of unextracted 86Rb (18.7%)

  12. Measurement of real pulsatile blood flow using X-ray PIV technique with CO2 microbubbles.

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Seo, Seung-Jun; Lim, Jae-Hong; Lee, Sang-Joon

    2015-03-06

    Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases.

  13. Measurement of real pulsatile blood flow using X-ray PIV technique with CO2 microbubbles

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Seo, Seung-Jun; Lim, Jae-Hong; Lee, Sang-Joon

    2015-01-01

    Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases. PMID:25744850

  14. Effects of respiratory manoeuvres on hepatic vein Doppler waveform and flow velocities in a healthy population

    International Nuclear Information System (INIS)

    Altinkaya, Naime; Koc, Zafer; Ulusan, Serife; Demir, Senay; Gurel, Kamil

    2011-01-01

    Objective: This study was performed to determine the variations in Doppler waveforms and flow velocity during respiratory manoeuvres in healthy individuals with no liver disease. Materials and methods: In total, 100 individuals (75 women and 25 men) without known cardiac or liver disease were examined prospectively with duplex Doppler ultrasonography (US). We recorded the Doppler waveforms and peak systolic velocities (V max ) of the middle hepatic vein during normal respiration, during breath-holding after quiet expiration and also during deep inspiration. Doppler waveforms are categorised as triphasic, biphasic or monophasic. Results: During normal respiration, hepatic venous waveforms were triphasic in 93% of subjects, monophasic in 6% and biphasic in 1%. During breath-holding after quiet expiration, the percentages were 91%, 6% and 3%, respectively. During deep inspiration, they were 80%, 18% and 2%, respectively. Although significant differences were noted between rates during deep inspiration and normal respiration, they were quite similar during normal respiration and breath-holding after quiet expiration (P max were significantly higher during normal respiration compared to quiet expiration and during quiet expiration compared to deep inspiration (P < 0.05). Conclusion: The velocities and waveforms of hepatic veins varied during respiratory manoeuvres. The status of respiration must be taken into consideration whilst examining the hepatic vein waveforms and velocities with duplex Doppler US.

  15. The gingival vein as a minimally traumatic site for multiple blood sampling in guinea pigs and hamsters.

    Science.gov (United States)

    Rodrigues, Mariana Valotta; de Castro, Simone Oliveira; de Albuquerque, Cynthia Zaccanini; Mattaraia, Vânia Gomes de Moura; Santoro, Marcelo Larami

    2017-01-01

    Laboratory animals are still necessary in scientific investigation and vaccine testing, but while novel methodological approaches are not available for their replacement, the search for new, humane, easy, and painless methods is necessary to diminish their stress and pain. When multiple blood samples are to be collected from hamsters and guinea pigs, the number of available venipuncture sites-which are greatly diminished in these species in comparison with other rodents due to the absence of a long tail-, harasses animal caregivers and researchers. Thus, this study aimed to evaluate if gingival vein puncture could be used as an additional route to obtain multiple blood samples from anesthetized hamsters and guinea pigs in such a way that animal behavior, well-being or hematological parameters would not be altered. Thus, twelve anesthetized Syrian golden hamsters and English guinea pigs were randomly allocated in two groups: a control group, whose blood samples were not collected, and an experimental group in which blood samples (200 microliters) were collected by gingival vein puncture at weekly intervals over six weeks. Clinical assessment, body weight gain and complete blood cell count were evaluated weekly, and control and experimental animals were euthanized at week seven, when the mentolabial region was processed to histological analyses. Multiple blood sampling from the gingival vein evoked no clinical manifestations or alteration in the behavioral repertoire, nor a statistically significant difference in weight gain in both species. Guinea pigs showed no alteration in red blood cell, leukocyte or platelet parameters over time. Hamsters developed a characteristic pattern of age-related physiological changes, which were considered normal. Histological analyses showed no difference in morphological structures in the interdental gingiva, confirming that multiple blood sampling is barely traumatic. Thus, these results evidence that blood collection from multiple

  16. Congestive index of portal vein

    International Nuclear Information System (INIS)

    Kim, Won Ho; Kim, H. K.; Lee, S. C.; Han, S. H.; Han, K. H.; Chung, J. B.; Choi, H. J.

    1989-01-01

    In patients with portal hypertension, the blood flow volume is maintained despite decreased blood flow velocity due to enlargement of the vascular cross sectional area. Thus, the 'congestion index' of the portal vein, which is the ratio between the cross sectional area (cm2) and the blood flow velocity (cm/sec) determined by a Doppler ultrasonography, may be a sensitive index by which to assess portal hypertension. We performed Doppler ultrasonography on 24 normal subjects, 14 patients with biopsy proved chronic active hepatitis and 55 patients with liver cirrhosis in order to assess the diagnostic value of the congestion index. The cross sectional area of the portal vein was significantly enlarged and the mean blood flow velocity was significantly reduced in patients with liver cirrhosis compared with controls. However, the blood flow volume was no difference. The congestion index of the portal vein was significantly increased in patients with liver cirrhosis (0.113+0.035) compared with patients with chronic active hepatitis(0.078+0.029) (p<0.001) and controls (0.053+0.016) (p<0.001). The sensitivity, specificity and predictability of the congestion index for detection of patients with the cirrhosis of the liver were 76.4%, 100% and 100% respectively, when the normal range was set at mean+2SD. The results suggest that the congestion index of the portal vein may pla a significant role in diagnosis of portal hypertensive patients

  17. Physiological and Pathological Impact of Blood Sampling by Retro-Bulbar Sinus Puncture and Facial Vein Phlebotomy in Laboratory Mice

    DEFF Research Database (Denmark)

    Teilmann, Anne Charlotte; Nygaard Madsen, Andreas; Holst, Birgitte

    2014-01-01

    weight following blood sampling, but the body weight loss was higher in mice subjected to facial vein phlebotomy. The food consumption was not significantly different between the two groups. At gross necropsy, subcutaneous hematomas were found in both groups and the histopathological analyses revealed...

  18. Importance of blood cultures from peripheral veins in pediatric patients with cancer and a central venous line

    DEFF Research Database (Denmark)

    Handrup, Mette Møller; Møller, Jens Kjølseth; Rutkjaer, Cecilie

    2015-01-01

    When an infection is suspected in a child with cancer and a central venous line (CVL), cultures are often only obtained from the CVL and not from a peripheral vein (PV). This study was undertaken to evaluate the importance of concomitant blood cultures from the CVL and a PV....

  19. Insight of Human Stroke from blood flow and blood pressure

    Science.gov (United States)

    Chen, Zhi; Ivanov, Plamen Ch.; Hu, Kun; Stanley, H. Eugene

    2003-03-01

    Stroke is is one of the leading cause of death and disability in the world. It is well believed that stroke is caused by the disturbance of cerebrovascular autoregulation. We investigate the blood flow on the left and right middle cerebral artery and beat-to-beat blood pressure simultaneously measured from the finger, for both subjects with stroke and healthy subjects. Synchronization technique is used to distinguish the difference between these two groups.

  20. Trial on MR portal blood flow measurement with phase contrast technique

    International Nuclear Information System (INIS)

    Tsunoda, Masatoshi; Kimoto, Shin; Togami, Izumi

    1991-01-01

    Portal blood flow measurement is considered to be important for the analysis of hemodynamics in various liver diseases. The Doppler ultrasound method has been used extensively during the past several years for measuring portal blood flow, as a non-invasive method. However, the Doppler ultrasound technique do not allow the portal blood flow to be measured in cases of obesity, with much intestinal gas, and so on. In this study, we attempted to measure the blood flow in the main trunk of portal vein as an application of MR phase contrast technique to the abdominal region. In the flow phantom study, the flow volumes and the velocities measured by phase contrast technique showed a close correlation with those measured by electromagnetic flowmeter. In the clinical study with 10 healthy volunteers, various values of portal blood flow were obtained. Mean portal blood flow could be measured within the measuring time (about 8 minutes) under natural breathing conditions. Phase contrast technique is considered to be useful for the non-invasive measurement of portal blood flow. (author)

  1. Role of blood transfusion product type and amount in deep vein thrombosis after cardiac surgery.

    Science.gov (United States)

    Ghazi, Lama; Schwann, Thomas A; Engoren, Milo C; Habib, Robert H

    2015-12-01

    Postoperative deep vein thrombosis (DVT) is associated with significant morbidity. Even with maximal thromboprophylaxis, postoperative DVT is present in 10% of cardiac surgery patients, and is linked to receiving transfusion. We hypothesized that the incidence of DVT varies with the transfused blood product type, and increases with transfusion dose. 139/1070 cardiac surgery patients have DVT despite maximal chemo and mechanical prophylaxis. DVTs were detected via serial perioperative duplex venous scans (DVS). Red blood cells (RBC), platelets (PLT), plasma (FFP) and cryoprecipitate transfusion data were collected. Transfusion was used in 506(47%) patients: RBC [468(44%); 4.0 ± 4.2u]; FFP [155(14.5%); 3.5 ± 2.3 u]; PLT [185(17.3%); 2.2 ± 1.3 u] and Cryoprecipitate [51(4.8%); 1.3 ± 0.6 u]. Isolated RBC transfusion accounted for 92.6% patients receiving one product, and their DVT rate was increased considerably compared to no transfusion (16.7% versus 7.3%; Pproduct transfusions; particularly when both RBC and FFP are used (25%-40%). Relative to no RBC (n=602), multivariate logistic regression analysis identified a significant RBC-DVT dose dependent relation (Pfashion that is exacerbated when accompanied with FFP. Postoperative screening diagnostic DVS are warranted in this transfused, high risk for DVT population to facilitate timely therapeutic intervention. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Effect of regional heating on the liver blood flow in rats

    International Nuclear Information System (INIS)

    Nakajima, T.; Song, C.W.; Osborn, J.L.; Rhee, J.G.; Levitt, S.H.

    1987-01-01

    The authors measured the blood flow in the liver of rats heated with a radio frequency capacitive heating device. The blood flow through the hepatic artery, as measured with the radioactive microsphere method, was 0.21 ml/min/gm; it increased by 13% and 16% when heated for 15 minutes at 41 0 C and 43 0 C, respectively. The portal vein blood flow was 1.09 ml/min/gm and decreased by 12% and 20% on heating for 15 minutes at 41 0 C and 43 0 C, respectively. The total liver blood flow, therefore, decreased by 11% at 41 0 C and by 14% at 43 0 C from the control value of 1.30 ml/min/gm

  3. Measurement of organ blood flow using tritiated water. II. Uterine blood flow in conscious pregnant ewes

    International Nuclear Information System (INIS)

    Brown, B.W.; Oddy, V.H.; Jones, A.W.

    1982-01-01

    Total uterine blood flow was measured with a tritiated water (TOH) diffusion method and with radioactive microspheres in six, conscious, pregnant ewes. With continuous infusion of TOH, equilibrium between the TOH concentration in utero-ovarian venous blood and arterial blood was attained within 50 min of the start of the infusion. The concentration of TOH in uterine and foetal tissue and in foetal blood water was the same as that in uterine venous water by 40 min; at this time, the concentration of TOH in the water of amniotic and allantoic fluids was 96% of that in uterine venous blood water. Estimates of total uterine blood flow obtained using TOH were highly correlated with those obtained with microspheres and the corresponding mean flow values obtained with the two techniques did not significantly differ. The percentage of the total uterine blood flow passing through arteriovenous anastomoses ranged from 1.4 to 3.3%

  4. Aortic blood flow subtraction: an alternative method for measuring total renal blood flow in conscious dogs

    DEFF Research Database (Denmark)

    Sandgaard, N C F; Andersen, J L; Holstein-Rathlou, N-H

    2002-01-01

    We have measured total renal blood flow (TRBF) as the difference between signals from ultrasound flow probes implanted around the aorta above and below the renal arteries. The repeatability of the method was investigated by repeated, continuous infusions of angiotensin II and endothelin-1 seven...... arterial blood pressure by 49% and decreased TRBF by 12%, providing an increase in renal vascular resistance of 69%. Dynamic analysis showed autoregulation of renal blood flow in the frequency range ... of TRBF by aortic blood flow subtraction is a practical and reliable method that allows direct comparison of excretory function and renal blood flow from two kidneys. The method also allows direct comparison between TRBF and flow in the caudal aorta....

  5. Central retinal vein occlusion with cilioretinal infarction from branch flow exclusion and choroidal arterial steal.

    Science.gov (United States)

    McLeod, David

    2009-01-01

    The first definitive study of retinal vein occlusion complicated by infarction within the territory of one or more cilioretinal arteries was published in 1976. Many individual cases and further case series have been reported in the interim, but the nature of the interrelationship is still under debate. A review was undertaken of the relevant clinical and fundus fluorescein angiographic characteristics of this combined retinal vascular disorder together with the pathophysiological mechanisms currently presented in the literature to explain their association. Scientific publications up to 2008 were evaluated by one of the authors of the original report. There are broad similarities between publications in their descriptions of the clinical features, but significant differences of detail and interpretation are also evident. Most of the mechanisms so far proposed to account for cilioretinal infarction after central or hemisphere retinal vein occlusion do not withstand critical scrutiny. Two related hypotheses are expounded that appear to satisfactorily elucidate this interrelationship -- branch flow exclusion and branch flow diversion (otherwise termed "choroidal arterial steal"). In eyes with a cilioretinal supply, the probability that cilioretinal infarction will complicate retinal vein occlusion increases with increasing severity of venous obstruction and the more distally the cilioretinal artery arises from the posterior ciliary arterial tree. A distal branch point also facilitates observation of dye front reciprocation within the artery. Indicators of the degree of venous obstruction that may be necessary to instigate cilioretinal infarction include very prolonged dye transit times in the central retinal circulation, exaggerated venous cyanosis and tortuosity, perivenous cotton-wool sentinels, and macular perivenular whitening.

  6. Huge Varicose Inferior Mesenteric Vein: an Unanticipated 99mTc-labeled Red Blood Cell Scintigraphy Finding

    International Nuclear Information System (INIS)

    Hoseinzadeh, Samaneh; Shafiei, Babak; Salehian, Mohamadtaghi; Neshandar Asli, Isa; Ghodoosi, Iraj

    2010-01-01

    Ectopic varices (EcV) are enlarged portosystemic venous collaterals, which usually develop secondary to portal hypertension (PHT). Mesocaval collateral vessels are unusual pathways to decompress the portal system. Here we report the case of a huge varicose inferior mesenteric vein (IMV) that drained into peri rectal collateral veins, demonstrated by 99m Tc-labeled red blood cell (RBC) scintigraphy performed for lower gastrointestinal (GI) bleeding in a 14-year-old girl. This case illustrates the crucial role of 99m Tc-labeled RBC scintigraphy for the diagnosis of rare ectopic lower GI varices.

  7. Huge Varicose Inferior Mesenteric Vein: an Unanticipated {sup 99m}Tc-labeled Red Blood Cell Scintigraphy Finding

    Energy Technology Data Exchange (ETDEWEB)

    Hoseinzadeh, Samaneh; Shafiei, Babak; Salehian, Mohamadtaghi; Neshandar Asli, Isa; Ghodoosi, Iraj [Shaheed Beheshti Medical University, Tehran (Iran, Islamic Republic of)

    2010-09-15

    Ectopic varices (EcV) are enlarged portosystemic venous collaterals, which usually develop secondary to portal hypertension (PHT). Mesocaval collateral vessels are unusual pathways to decompress the portal system. Here we report the case of a huge varicose inferior mesenteric vein (IMV) that drained into peri rectal collateral veins, demonstrated by {sup 99m}Tc-labeled red blood cell (RBC) scintigraphy performed for lower gastrointestinal (GI) bleeding in a 14-year-old girl. This case illustrates the crucial role of {sup 99m}Tc-labeled RBC scintigraphy for the diagnosis of rare ectopic lower GI varices.

  8. Regional cerebral blood flow in schizophrenic patients

    International Nuclear Information System (INIS)

    Sagawa, Katsuo; Sibuya, Isoo; Oiji, Arata; Kawakatsu, Sinobu; Morinobu, Shigeru; Totsuka, Shiro; Kinoshita, Osami; Yazaki, Mitsuyasu.

    1990-01-01

    Seventy-six schizophrenic patients were examined by a Xe-133 inhalation method to determine regional cerebral blood flow. A decreased blood flow was observed in the frontal lobe, especially in the right inferior part. In a study on the relationship between disease subtypes and regional cerebral blood flow, negative symptoms were found more predominantly associated with dissolution type than delusion type. In the group of dissolution type, a decreased blood flow was observed in both the right inferior frontal lobe and the right upper hemisphere, in comparison to the group of delution type. Patients presenting with auditory hallucination had a significantly higher incidence of both negative and positive symptoms, as compared with those not presenting with it. In such patients, a significantly decreased blood flow was also seen in the left upper frontal lobe and the bilateral parietal lobe. Xe-133 inhalation method should assist in evaluating brain function in schizophrenic patients, thus leading to the likelihood of developing a new treatment modality. (N.K.)

  9. [Baroreflexes originated in vertebral artery zones upon peripheral vein tonus, systemic arterial blood pressure, and external respiration].

    Science.gov (United States)

    Agadzhanian, N A; Kupriianov, S V

    2008-06-01

    The investigation was intended to study the role ofbaroreceptors ofhemodynamically isolated zone of vertebral arteries in regulation of peripheral veins tonus, arterial pressure and external respiration. Pressure decrease in this vascular reflexogenic zone led to reflex responses of increase in femoral vein tonus, elevation of blood pressure level and stimulation of external respiration. The opposite reflex responses of cardio-respiratory functional system to initial pressure activation of vertebral arteries baroreceptors are observed. Basing on generalization of our own findings and similar physiological and morphological researches of other authors, it is established that afferentation from the vertebral artery zone is a reflexogenic factor of somatic muscles' veins tonus regulation. These reflexes of capacity vessels tonic activity changes are part of cardio-respiratory responses of maintaining the tissue gaseous exchange.

  10. In silico particle margination in blood flow

    OpenAIRE

    Müller, Kathrin

    2015-01-01

    A profound knowledge of margination, the migration of blood components to the vessel wall in blood flow, is required in order to understand the genesis of various diseases, as e.g., cardiovascular diseases or bleeding disorders. Margination of particles is a pre-condition for potential adhesion. Adhesion to the vessel wall is required for platelets, the protein von Willebrand factor (VWF), but also for drug and imaging agent carriers in order to perform their particular tasks. In the haemosta...

  11. Electromechanical Model of Blood Flow in Vessels

    OpenAIRE

    Ivo Cap; Barbora Czippelova

    2008-01-01

    The present paper deals with some theoretical derivations connected with very efficient method of solution of hydrodynamic problems of blood flow in human cardiovascular system. The electromechanical analogy of liquid flow in a tube and electromagnetic wave propagating along an electric transmission line is discussed. We have derived a detailed circuit-like model of an elementary section of the elastic tube with viscose Newtonian liquid. The analogy harmonic current electrical cir...

  12. Electromechanical Model of Blood Flow in Vessels

    Directory of Open Access Journals (Sweden)

    Ivo Cap

    2008-01-01

    Full Text Available The present paper deals with some theoretical derivations connected with very efficient method of solution of hydrodynamic problems of blood flow in human cardiovascular system. The electromechanical analogy of liquid flow in a tube and electromagnetic wave propagating along an electric transmission line is discussed. We have derived a detailed circuit-like model of an elementary section of the elastic tube with viscose Newtonian liquid. The analogy harmonic current electrical circuit has been designed

  13. Cerebral blood flow response to functional activation

    DEFF Research Database (Denmark)

    Paulson, Olaf B; Hasselbalch, Steen G; Rostrup, Egill

    2010-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only inc...... the cerebral tissue's increased demand for glucose supply during neural activation with recent evidence supporting a key function for astrocytes in rCBF regulation....

  14. Classification of hypervascular liver lesions based on hepatic artery and portal vein blood supply coefficients calculated from triphasic CT scans.

    Science.gov (United States)

    Boas, F Edward; Kamaya, Aya; Do, Bao; Desser, Terry S; Beaulieu, Christopher F; Vasanawala, Shreyas S; Hwang, Gloria L; Sze, Daniel Y

    2015-04-01

    Perfusion CT of the liver typically involves scanning the liver at least 20 times, resulting in a large radiation dose. We developed and validated a simplified model of tumor blood supply that can be applied to standard triphasic scans and evaluated whether this can be used to distinguish benign and malignant liver lesions. Triphasic CTs of 46 malignant and 32 benign liver lesions were analyzed. For each phase, regions of interest were drawn in the arterially enhancing portion of each lesion, as well as the background liver, aorta, and portal vein. Hepatic artery and portal vein blood supply coefficients for each lesion were then calculated by expressing the enhancement curve of the lesion as a linear combination of the enhancement curves of the aorta and portal vein. Hepatocellular carcinoma (HCC) and hypervascular metastases, on average, both had increased hepatic artery coefficients compared to the background liver. Compared to HCC, benign lesions, on average, had either a greater hepatic artery coefficient (hemangioma) or a greater portal vein coefficient (focal nodular hyperplasia or transient hepatic attenuation difference). Hypervascularity with washout is a key diagnostic criterion for HCC, but it had a sensitivity of 72 % and specificity of 81 % for diagnosing malignancy in our diverse set of liver lesions. The sensitivity for malignancy was increased to 89 % by including enhancing lesions that were hypodense on all phases. The specificity for malignancy was increased to 97 % (p = 0.039) by also examining hepatic artery and portal vein blood supply coefficients, while maintaining a sensitivity of 76 %.

  15. Embolization techniques for high-flow arteriovenous malformations with a dominant outflow vein.

    Science.gov (United States)

    Conway, Allan M; Qato, Khalil; Drury, Jennifer; Rosen, Robert J

    2015-04-01

    The aim of this study was to assess the management and outcomes of arteriovenous malformations (AVMs) with a dominant outflow vein (DOV) treated with retrograde venous embolization. A retrospective review was performed from November 2010 to May 2014 on all patients with a high-flow AVM and associated DOV who underwent transvenous embolization of the DOV. Indications, techniques, complications, and outcomes were reviewed. Fourteen patients (five male; 36%) underwent transvenous embolization of high-flow AVMs with a DOV. Median age was 41.6 years (15.7-65.8 years). The AVM was located on an extremity in eight patients (57%) and in the pelvis in six patients (43%). The indication for the procedure was pain in 11 patients (79%), swelling in 3 patients (21%), a nonhealing wound in 1 patient (7%), and impotence in 1 patient (7%). The median number of prior procedures to treat the AVM was 2.5 (0-13). Transvenous embolization with coils was performed in 13 patients (93%). The Amplatzer vascular plug and Amplatzer septal occluder (St. Jude Medical, St. Paul, Minn) were used in four patients (29%). Concurrent percutaneous puncture embolization of the AVM nidus was used in seven patients (50%) and transcatheter arterial embolization in eight patients (57%). Technical angiographic success was seen in all patients. Five patients (36%) experienced a complete response to treatment, whereas eight (57%) experienced a partial response. Seven patients (50%) required further procedures for residual symptoms. AVMs with a DOV can be successfully treated by a transvenous approach. Percutaneous puncture embolization of the nidus or draining vein and transcatheter arterial embolization may assist in reducing flow. Copyright © 2015 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

  16. Studies on blood supply of liver metastasis with DSA, CT and portal vein perfusion CT during superior mesenteric arterial portography

    International Nuclear Information System (INIS)

    Li Zhigang; Shi Gaofeng; Huang Jingxiang; Li Shunzong; Liang Guoqing; Wang Hongguang; Han Pengyin; Wang Qi; Gu Tieshu

    2008-01-01

    Objective: To probe the blood supply of liver metastasis by celiac artery, proper hepatic artery DSA, portal vein perfusion CT during superior mesenteric arterial portography (PCTAP). Methods: One hundred patients with liver metastases were examined prospectively by plain CT scan, multiphase enhanced CT scan, celiac arteriography and proper hepatic arteriography. Of them, 56 patients were examined by PCTAP. All primary lesions were confirmed by operation and (or) pathology examination. In order to investigate the blood supply of metastasis lesions, the software of Photoshop was used to obtain the time-attenuation curves (TDC) of tumor center, tumor edge, portal vein and normal liver parenchyma adjacent to the tumor to calculate liver perfusion for DSA image analysis, while a deconvolution model from CT perfusion software was designed for the dual blood supply. Results: DSA findings: TDC of proper hepatic arteriography showed: the mean peak concentration (K value) in tumor centers was (67 ± 12)%, and it was (76 ± 15)% for peritumor tissue, (51 ± 10)% in normal liver parenchyma. TDC of celiac arteriogaphy showed that the contrast concentration of tumor centers and tumor edge increased fast in early stage, then maintained a slight upward plateau, in the meanwhile, the contrast concentration of normal liver parenchyma kept increasing slowly. PCTAP findings: tumors exhibited no enhancement during 30 s continued scans. Conclusion: The blood supply of liver metastasis mainly comes from hepatic artery, but barely from portal vein. (authors)

  17. The subtyping of primary aldosteronism by adrenal vein sampling: sequential blood sampling causes factitious lateralization.

    Science.gov (United States)

    Rossitto, Giacomo; Battistel, Michele; Barbiero, Giulio; Bisogni, Valeria; Maiolino, Giuseppe; Diego, Miotto; Seccia, Teresa M; Rossi, Gian Paolo

    2018-02-01

    The pulsatile secretion of adrenocortical hormones and a stress reaction occurring when starting adrenal vein sampling (AVS) can affect the selectivity and also the assessment of lateralization when sequential blood sampling is used. We therefore tested the hypothesis that a simulated sequential blood sampling could decrease the diagnostic accuracy of lateralization index for identification of aldosterone-producing adenoma (APA), as compared with bilaterally simultaneous AVS. In 138 consecutive patients who underwent subtyping of primary aldosteronism, we compared the results obtained simultaneously bilaterally when starting AVS (t-15) and 15 min after (t0), with those gained with a simulated sequential right-to-left AVS technique (R ⇒ L) created by combining hormonal values obtained at t-15 and at t0. The concordance between simultaneously obtained values at t-15 and t0, and between simultaneously obtained values and values gained with a sequential R ⇒ L technique, was also assessed. We found a marked interindividual variability of lateralization index values in the patients with bilaterally selective AVS at both time point. However, overall the lateralization index simultaneously determined at t0 provided a more accurate identification of APA than the simulated sequential lateralization indexR ⇒ L (P = 0.001). Moreover, regardless of which side was sampled first, the sequential AVS technique induced a sequence-dependent overestimation of lateralization index. While in APA patients the concordance between simultaneous AVS at t0 and t-15 and between simultaneous t0 and sequential technique was moderate-to-good (K = 0.55 and 0.66, respectively), in non-APA patients, it was poor (K = 0.12 and 0.13, respectively). Sequential AVS generates factitious between-sides gradients, which lower its diagnostic accuracy, likely because of the stress reaction arising upon starting AVS.

  18. Cerebral blood flow in acute mountain sickness

    DEFF Research Database (Denmark)

    Jensen, J B; Wright, Anne; Lassen, N A

    1990-01-01

    Changes in cerebral blood flow (CBF) were measured using the radioactive xenon technique and were related to the development of acute mountain sickness (AMS). In 12 subjects, ascending from 150 to 3,475 m, CBF was 24% increased at 24 h [45.1 to 55.9 initial slope index (ISI) units] and 4% increased...

  19. Pulsatile spiral blood flow through arterial stenosis.

    Science.gov (United States)

    Linge, Fabian; Hye, Md Abdul; Paul, Manosh C

    2014-11-01

    Pulsatile spiral blood flow in a modelled three-dimensional arterial stenosis, with a 75% cross-sectional area reduction, is investigated by using numerical fluid dynamics. Two-equation k-ω model is used for the simulation of the transitional flow with Reynolds numbers 500 and 1000. It is found that the spiral component increases the static pressure in the vessel during the deceleration phase of the flow pulse. In addition, the spiral component reduces the turbulence intensity and wall shear stress found in the post-stenosis region of the vessel in the early stages of the flow pulse. Hence, the findings agree with the results of Stonebridge et al. (2004). In addition, the results of the effects of a spiral component on time-varying flow are presented and discussed along with the relevant pathological issues.

  20. Collision Based Blood Cell Distribution of the Blood Flow

    Science.gov (United States)

    Cinar, Yildirim

    2003-11-01

    Introduction: The goal of the study is the determination of the energy transferring process between colliding masses and the application of the results to the distribution of the cell, velocity and kinetic energy in arterial blood flow. Methods: Mathematical methods and models were used to explain the collision between two moving systems, and the distribution of linear momentum, rectilinear velocity, and kinetic energy in a collision. Results: According to decrease of mass of the second system, the velocity and momentum of constant mass of the first system are decreased, and linearly decreasing mass of the second system captures a larger amount of the kinetic energy and the rectilinear velocity of the collision system on a logarithmic scale. Discussion: The cause of concentration of blood cells at the center of blood flow an artery is not explained by Bernoulli principle alone but the kinetic energy and velocity distribution due to collision between the big mass of the arterial wall and the small mass of blood cells must be considered as well.

  1. Ocular Blood Flow and Normal Tension Glaucoma

    Directory of Open Access Journals (Sweden)

    Ning Fan

    2015-01-01

    Full Text Available Normal tension glaucoma (NTG is known as a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, even though the intraocular pressure (IOP does not exceed the normal range. The pathophysiology of NTG remains largely undetermined. It is hypothesized that the abnormal ocular blood flow is involved in the pathogenesis of this disease. A number of evidences suggested that the vascular factors played a significant role in the development of NTG. In recent years, the new imaging techniques, fluorescein angiography, color Doppler imaging (CDI, magnetic resonance imaging (MRI, and laser speckle flowgraphy (LSFG, have been used to evaluate the ocular blood flow and blood vessels, and the impaired vascular autoregulation was found in patients with NTG. Previous studies showed that NTG was associated with a variety of systemic diseases, including migraine, Alzheimer’s disease, primary vascular dysregulation, and Flammer syndrome. The vascular factors were involved in these diseases. The mechanisms underlying the abnormal ocular blood flow in NTG are still not clear, but the risk factors for glaucomatous optic neuropathy likely included oxidative stress, vasospasm, and endothelial dysfunction.

  2. 4D flow MRI assessment of right atrial flow patterns in the normal heart - influence of caval vein arrangement and implications for the patent foramen ovale.

    Directory of Open Access Journals (Sweden)

    Jehill D Parikh

    Full Text Available To investigate atrial flow patterns in the normal adult heart, to explore whether caval vein arrangement and patency of the foramen ovale (PFO may be associated with flow pattern.Time-resolved, three-dimensional velocity encoded magnetic resonance imaging (4D flow was employed to assess atrial flow patterns in thirteen healthy subjects (6 male, 40 years, range 25-50 and thirteen subjects (6 male, 40 years, range 21-50 with cryptogenic stroke and patent foramen ovale (CS-PFO. Right atrial flow was defined as vortical, helico-vortical, helical and multiple vortices. Time-averaged and peak systolic and diastolic flows in the caval and pulmonary veins and their anatomical arrangement were compared.A spectrum of right atrial flow was observed across the four defined categories. The right atrial flow patterns were strongly associated with the relative position of the caval veins. Right atrial flow patterns other than vortical were more common (p = 0.015 and the separation between the superior and inferior vena cava greater (10±5mm versus 3±3mm, p = 0.002 in the CS-PFO group. In the left atrium all subjects except one had counter-clockwise vortical flow. Vortex size varied and was associated with left lower pulmonary vein flow (systolic r = 0.61, p = 0.001, diastolic r = 0.63 p = 0.002. A diastolic vortex was less common and time-averaged left atrial velocity was greater in the CS-PFO group (17±2cm/sec versus 15±1, p = 0.048. One CS-PFO subject demonstrated vortical retrograde flow in the descending aortic arch; all other subjects had laminar descending aortic flow.Right atrial flow patterns in the normal heart are heterogeneous and are associated with the relative position of the caval veins. Patterns, other than 'typical' vortical flow, are more prevalent in the right atrium of those with cryptogenic stroke in the context of PFO. Left atrial flow patterns are more homogenous in normal hearts and show a relationship with flow arising from the left

  3. Dynamic Infrared Thermography Study of Blood Flow Relative to Lower Limp Position

    Science.gov (United States)

    Stathopoulos, I.; Skouroliakou, K.; Michail, C.; Valais, I.

    2015-09-01

    Thermography is an established method for studying skin temperature distribution. Temperature distribution on body surface is influenced by a variety of physiological mechanisms and has been proven a reliable indicator of various physiological disorders. Blood flow is an important factor that influences body heat diffusion and skin temperature. In an attempt to validate and further elucidate thermal models characterizing the human skin, dynamic thermography of the lower limp in horizontal and vertical position was performed, using a FLIR T460 thermographic camera. Temporal variation of temperature was recorded on five distinct points of the limp. Specific points were initially cooled by the means of an ice cube and measurements of the skin temperature were obtained every 30 seconds as the skin temperature was locally reduced and afterwards restored at its initial value. The return to thermal balance followed roughly the same pattern for all points of measurement, although the heating rate was faster when the foot was in horizontal position. Thermal balance was achieved faster at the spots that were positioned on a vein passage. Our results confirm the influence of blood flow on the thermal regulation of the skin. Spots located over veins exhibit different thermal behaviour due to thermal convection through blood flow. Changing the position of the foot from vertical to horizontal, effectively affects blood perfusion as in the vertical position blood circulation is opposed by gravity.

  4. Cerebral blood flow changes in cluster headache

    International Nuclear Information System (INIS)

    Norris, J.W.; Hachinski, V.C.; Cooper, P.W.

    1976-01-01

    Serial cerebral blood flod studies performed by the intra-carotid 133 Xenon method were fortuitously determined during the course of a cluster headache in a 32 year old man. The initial study was performed about 10 min after the headache began and showed values at the upper limit of normal. Twenty min after the headache started a second procedure showed that the autoregulatory response on hyperventilation was normal. Ergotamine tartrate was given intra-muscularly 23 min after the headache began and there was partial relief. A third cerebral blood flow estimation showed abnormally high values. The probable reasons for this are discussed. (author)

  5. Differential visceral blood flow in the hyperdynamic circulation of patients with liver cirrhosis.

    Science.gov (United States)

    McAvoy, N C; Semple, S; Richards, J M J; Robson, A J; Patel, D; Jardine, A G M; Leyland, K; Cooper, A S; Newby, D E; Hayes, P C

    2016-05-01

    With advancing liver disease and the development of portal hypertension, there are major alterations in somatic and visceral blood flow. Using phase-contrast magnetic resonance angiography, we characterised alterations in blood flow within the hepatic, splanchnic and extra-splanchnic circulations of patients with established liver cirrhosis. To compare blood flow in splanchnic and extra-splanchnic circulations in patients with varying degrees of cirrhosis and healthy controls. In a single-centre prospective study, 21 healthy volunteers and 19 patients with established liver disease (Child's stage B and C) underwent electrocardiogram-gated phase-contrast-enhanced 3T magnetic resonance angiography of the aorta, hepatic artery, portal vein, superior mesenteric artery, and the renal and common carotid arteries. In comparison to healthy volunteers, resting blood flow in the descending thoracic aorta was increased by 43% in patients with liver disease (4.31 ± 1.47 vs. 3.31 ± 0.80 L/min, P = 0.011). While portal vein flow was similar (0.83 ± 0.38 vs. 0.77 ± 0.35 L/min, P = 0.649), hepatic artery flow doubled (0.50 ± 0.46 vs. 0.25 ± 0.15 L/min, P = 0.021) and consequently total liver blood flow increased by 30% (1.33 ± 0.84 vs. 1.027 ± 0.5 L/min, P = 0.043). In patients with liver disease, superior mesenteric artery flow was threefold higher (0.65 ± 0.35 vs. 0.22 ± 0.13 L/min, P phenomenon. These circulatory disturbances may underlie many of the manifestations of advanced liver disease. © 2016 John Wiley & Sons Ltd.

  6. Numerical investigations of the unsteady blood flow in the end-to-side arteriovenous fistula for hemodialysis.

    Science.gov (United States)

    Jodko, Daniel; Obidowski, Damian; Reorowicz, Piotr; Jóźwik, Krzysztof

    2016-01-01

    The aim of this study was to investigate the blood flow in the end-to-side arteriovenous (a-v) fistula, taking into account its pulsating nature and the patient-specific geometry of blood vessels. Computational Fluid Dynamics (CFD) methods were used for this analysis. DICOM images of the fistula, obtained from the angio-computed tomography, were a source of the data applied to develop a 3D geometrical model of the fistula. The model was meshed, then the ANSYS CFX v. 15.0 code was used to perform simulations of the flow in the vessels under analysis. Mesh independence tests were conducted. The non-Newtonian rheological model of blood and the Shear Stress Transport model of turbulence were employed. Blood vessel walls were assumed to be rigid. Flow patterns, velocity fields, the volume flow rate, the wall shear stress (WSS) propagation on particular blood vessel walls were shown versus time. The maximal value of the blood velocity was identified in the anastomosis - the place where the artery is connected to the vein. The flow rate was calculated for all veins receiving blood. The blood flow in the geometrically complicated a-v fistula was simulated. The values and oscillations of the WSS are the largest in the anastomosis, much lower in the artery and the lowest in the cephalic vein. A strong influence of the mesh on the results concerning the maximal and area-averaged WSS was shown. The relation between simulations of the pulsating and stationary flow under time-averaged flow conditions was presented.

  7. Meal-induced changes in splanchnic blood flow and oxygen uptake in middle-aged healthy humans

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Søndergaard, SB; Møller, Søren

    2006-01-01

    OBJECTIVE: For decades, the determination of changes in splanchnic blood flow and oxygen uptake after a meal has been used in the management of patients with suspected chronic intestinal ischaemia. However, little is known about the normal meal-induced responses. The aim of the present study...... was therefore to measure the splanchnic blood flow and oxygen uptake before and after a standardized meal in a group of middle-aged normal volunteers. MATERIAL AND METHODS: Splanchnic blood flow and oxygen uptake were determined at baseline and after a 3600-kJ mixed meal in 8 healthy women (50-70 years) and 10...... healthy men (52-76 years). Splanchnic blood flow was measured during hepatic vein catheterization by indirect Fick principle with indocyanine green as the indicator. Splanchnic oxygen uptake was calculated from splanchnic blood flow and the arteriovenous oxygen difference. RESULTS: The meal induced...

  8. Multimodal in vivo blood flow sensing combining particle image velocimetry and optical tweezers-based blood steering

    Science.gov (United States)

    Meissner, Robert; Sugden, Wade W.; Siekmann, Arndt F.; Denz, Cornelia

    2018-02-01

    All higher developed organisms contain complex hierarchical networks of arteries, veins and capillaries. These constitute the cardiovascular system responsible for supplying nutrients, gas and waste exchange. Diseases related to the cardiovascular system are among the main causes for death worldwide. In order to understand the processes leading to arteriovenous malformation, we studied hereditary hemorrhagic telangiectasia (HHT), which has a prevalence of 1:5000 worldwide and causes internal bleeding. In zebrafish, HHT is induced by mutation of the endoglin gene involved in HHT and observed to reduce red blood cell (RBC) flow to intersegmental vessels (ISVs) in the tail due to malformations of the dorsal aorta (DA) and posterior cardinal vein (PCV). However, these capillaries are still functional. Changes in the blood flow pattern are observed from in vivo data from zebrafish embryos through particle image velocimetry (PIV). Wall shear rates (WSRs) and blood flow velocities are obtained non-invasively with millisecond resolution. We observe significant increases of blood flow velocity in the DA for endoglin-deficient zebrafish embryos (mutants) at 3 days post fertilization. In the PCV, this increase is even more pronounced. We identified an increased similarity between the DA and the PCV of mutant fish compared to siblings, i.e., unaffected fish. To counteract the reduced RBC flow to ISVs we implement optical tweezers (OT). RBCs are steered into previously unperfused ISVs showing a significant increase of RBC count per minute. We discuss limitations with respect to biocompatibility of optical tweezers in vivo and determination of in vivo wall shear stress (WSS) connected to normal and endoglin-deficicent zebrafish embryos.

  9. Ultrasound assessment of great saphenous vein insufficiency

    Directory of Open Access Journals (Sweden)

    Chander RK

    2015-06-01

    Full Text Available Rajiv K Chander,1 Thomas S Monahan1,2 1Section of Vascular Surgery, Department of Surgery, University of Maryland School of Medicine, 2Department of Surgery, Baltimore Veterans Affairs Medical Center, Baltimore, MD, USA Abstract: Duplex ultrasonography is the ideal modality to assess great saphenous vein insufficiency. Duplex ultrasonography incorporates both gray scale images to delineate anatomy and color-Doppler imaging that visualizes the flow of blood in a structure. Assessment of great saphenous vein requires definition of the anatomy, augmentation of flow, evaluation for both superficial and deep vein thrombosis, and determining the presence of reflux. Currently, evolution in the treatment of reflux also relies on ultrasound for the treatment of the disease. Understanding the utilization of the ultrasound for the diagnosis and treatment of greater saphenous vein reflux is important for practitioners treating reflux disease. Keywords: duplex ultrasonography, small saphenous vein 

  10. Cutaneous blood flow rate in areas with and without arteriovenous anastomoses during exercise

    DEFF Research Database (Denmark)

    Midttun, M.; Sejrsen, Per

    1998-01-01

    Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow......Arteriovenous anastomoses, capillaries, cutaneous bllod flow rate, exercise, finger blood flow, skin blood flow...

  11. Hepatobiliary system functional analysis by blood flow and clearance delay model

    International Nuclear Information System (INIS)

    Aboltins, A.; Reinholds, E.

    2002-01-01

    A mathematical model for describing liver uptake-excretion is developed and approved. Model is based on different timing delays in hepatobiliary and blood flow system elements. Series of scintigraphic images with 99m Tc-mebrofenins or 99m Tc-HIDA taken with standard nuclear medicine gamma camera are used as the real data for calculations. The time-activity curves are obtained from many regions of human body - heart, liver, gallbladder, spleen, aorta, vein, etc. Both first pass and dynamic acquisition data are used. Results are calculated using real system parameters and compared to real scintigraphy data. Mathematical simulations are made to show difference of hepatobiliary system function at three main points: normal function, good blood flow with bad hepatic function and bad blood flow with good hepatic function. (authors)

  12. Cine phase-contrast MR to assess portal blood flow in a 10-year-old girl with abdominal aortic coarctation: a case report

    International Nuclear Information System (INIS)

    Clark, T.W.I.; Culham, J.A.G.

    1998-01-01

    We report the case of a 10-year-old girl with repaired abdominal aortic coarctation in whom chronic mesenteric ischemia was clinically suspected. Cine phase-contrast magnetic resonance (MR) was used to determine the difference between fasting and postprandial portal blood flow. Fasting flow rates in the portal vein were normal. After a meal, blood flow in the portal vein increased 226 % over the fasting state, showing normal augmentation. To the best of our knowledge, this is the first application of this technique to a pediatric setting. (orig.)

  13. Regional blood flow studies with radioisotopes

    International Nuclear Information System (INIS)

    Holman, B.L.; McNiel, B.J.; Adelstein, S.J.

    1975-01-01

    The methodological approaches to blood flow analysis include (1) diffusible indicator methods, (2) clearance techniques and (3) nondiffusible indicator methods. In each case, accurate measurements of blood flow can be obtained by developing mathematical models which relate the time-dependent observation derived from following the fate of a radiotracer as a function of time to the physiological process itself. Application of these models to biological systems involves constraints and necessitates compromises which may affect the validity of the measurements. Nevertheless, when these techniques are carefully applied and adequately validated, they have provided critical physiological information about such organ systems as the brain and kidney and promise to provide diagnostic information in patients with suspected coronary and peripheral vascular disease

  14. Brain blood flow studies with single photon emission computed tomography in patients with plateau waves

    International Nuclear Information System (INIS)

    Hayashi, Minoru; Kobayashi, Hidenori; Kawano, Hirokazu; Handa, Yuji; Noguchi, Yoshiyuki; Shirasaki, Naoki; Hirose, Satoshi

    1986-01-01

    The authors studied brain blood flow with single photon emission computed tomography (SPECT) in two patients with plateau waves. The intracranial pressure and blood pressure were also monitored continuously in these patients. They included one patient with brain-tumor (rt. sphenoid ridge meningioma) and another with hydrocephalus after subarachnoid hemorrhage due to rupture of lt. internal carotid aneurysm. The intracranial pressure was monitored through an indwelling ventricular catheter attached to a pressure transducer. The blood pressure was recorded through an intraarterial catheter placed in the dorsalis pedis artery. Brain blood flow was studied with Headtome SET-011 (manufactured by Shimazu Co., Ltd.). For this flow measurement study, an intravenous injection of Xenon-133 of about 30 mCi was given via an antecubital vein. The position of the slice for the SPECT was selected so as to obtain information not only from the cerebral hemisphere but also from the brain stem : a cross section 25 deg over the orbito-meatal line, passing through the inferior aspect of the frontal horn, the basal ganglia, the lower recessus of the third ventricle and the brain stem. The results indicated that, in the cerebral hemisphere, plateau waves were accompanied by a decrease in blood flow, whereas, in the brain stem, the blood flow showed little change during plateau waves as compared with the interval phase between two plateau waves. These observations may explain why there is no rise in the blood pressure and why patients are often alert during plateau waves. (author)

  15. Determinants of pulmonary blood flow distribution.

    Science.gov (United States)

    Glenny, Robb W; Robertson, H Thomas

    2011-01-01

    The primary function of the pulmonary circulation is to deliver blood to the alveolar capillaries to exchange gases. Distributing blood over a vast surface area facilitates gas exchange, yet the pulmonary vascular tree must be constrained to fit within the thoracic cavity. In addition, pressures must remain low within the circulatory system to protect the thin alveolar capillary membranes that allow efficient gas exchange. The pulmonary circulation is engineered for these unique requirements and in turn these special attributes affect the spatial distribution of blood flow. As the largest organ in the body, the physical characteristics of the lung vary regionally, influencing the spatial distribution on large-, moderate-, and small-scale levels. © 2011 American Physiological Society.

  16. Regulation of bone blood flow in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Boushel, Robert; Hellsten, Ylva

    2018-01-01

    of cyclooxygenase (COX) enzyme, thus prostaglandin (PG) synthesis on femoral bone marrow blood flow by positron emission tomography in healthy young men at rest and during one leg dynamic exercise. In an additional group of healthy men, the role of adenosine (ADO) in the regulation of BBF during exercise......The mechanisms that regulate bone blood flow (BBF) in humans are largely unknown. Animal studies suggest that nitric oxide (NO) could be involved and in the present study we investigated the effects of inhibition of nitric oxide synthase (NOS) alone and in combination with inhibition.......036), but did not affect BBF significantly during exercise (5.5±1.4 ml/100g/min, p=0.25). On the other hand, while combined NOS and COX inhibition did not cause any further reduction of blood flow at rest (0.6±0.2 ml/100g/min), the combined blockade reduced BBF during exercise by ~21%, to 5.0±1.8 ml/100g/min (p...

  17. Method of measuring blood flow by radiation

    International Nuclear Information System (INIS)

    Gildenberg, P.L.

    1977-01-01

    A method of measuring relative blood flow through at least a part of the body using penetrating radiation comprises transmitting a plurality of rays at an initial angle or initial mean angle through a planar slice of the body to define a first set of rays, transmitting a plurality of further sets of rays at angles or mean angles different from each other and from the initial angle or initial mean angle through the same planar slice of the body to define by the intersection of all such rays a two-dimensional matrix of elements of the body in the slice, measuring for each ray emerging from the body a number of over the period of time at least equal to a pulse interval representing the momentary sum of the transmissions or absorptions of the element of the body intersected by the ray, determining from the momentary signals momentary signals a difference signal representing the maximum difference between the momentary signals for each ray over the period of time, deriving sets of discrete difference signals corresponding to the sets of rays, the difference signals being indicative of the transmission or absorption of blood flowing through each element of the body in the matrix, and calculating from the difference signals resultant signals representing the transmissions or absorptions due to blood flow in the elements of the matrix. These resultant signals may be visually depicted on a cathode ray tube display, as a digital print-out, or as a photograph. 30 claims, 8 figures

  18. Regional cerebral blood flow in schizophrenia

    International Nuclear Information System (INIS)

    Kanoh, Masayuki

    1989-01-01

    Regional cerebral blood flow (rCBF) was measured at rest using the 133 Xe inhalation technique in 40 DSM-III-diagnosed schizophrenics (22 males, 18 females: mean age 35.0 years, range 20-49 years) and 31 age-and sex-matched normal controls (16 males, 15 females: mean age 34.3 years, range 21-49 years). The absolute value (AV) and the percent value (PV) of the rCBF in schizophrenics were compared with those in controls. Correlations between rCBF and the Brief Psychiatric Rating Scale (BPRS) scores or the performance of Wisconsin Card Sorting Test (WCST) were examined in schizophrenics. Schizophrenics showed significantly lower AVs in all brain regions examined and a significantly lower PV in the left superior frontal region than controls. The hyperfrontal rCBF distribution which was found in both hemispheres in controls, was absent in the left hemisphere in schizophrenics. In schizophrenics, superior frontal blood flows were significantly negatively correlated with the negative symptom scores of the BPRS but not with the total scores and the positive symptom scores of the BPRS. In schizophrenics, inferior frontal blood flows were significantly correlated with the number of sorting categories achieved. These results indicate that rCBF in schizophrenia is reduced in the whole brain and especially in the left superior frontal region. These findings suggest a frontal lobe dysfunction in schizophrenia. (author)

  19. Computational Analysis of Human Blood Flow

    Science.gov (United States)

    Panta, Yogendra; Marie, Hazel; Harvey, Mark

    2009-11-01

    Fluid flow modeling with commercially available computational fluid dynamics (CFD) software is widely used to visualize and predict physical phenomena related to various biological systems. In this presentation, a typical human aorta model was analyzed assuming the blood flow as laminar with complaint cardiac muscle wall boundaries. FLUENT, a commercially available finite volume software, coupled with Solidworks, a modeling software, was employed for the preprocessing, simulation and postprocessing of all the models.The analysis mainly consists of a fluid-dynamics analysis including a calculation of the velocity field and pressure distribution in the blood and a mechanical analysis of the deformation of the tissue and artery in terms of wall shear stress. A number of other models e.g. T branches, angle shaped were previously analyzed and compared their results for consistency for similar boundary conditions. The velocities, pressures and wall shear stress distributions achieved in all models were as expected given the similar boundary conditions. The three dimensional time dependent analysis of blood flow accounting the effect of body forces with a complaint boundary was also performed.

  20. Cerebral blood flow in Binswanger's disease

    International Nuclear Information System (INIS)

    Kawabata, Keita; Tachibana, Hisao; Sugita, Minoru

    1991-01-01

    Eight patients with a clinical diagnosis of Binswanger's disease (BD) were evaluated with I-123 IMP SPECT. The SPECT findings were compared with those in 7 other patients with Alzheimer's disease (AD) and 9 normal subjects. The ratios of I-123 IMP in the temporal cortex, thalamus, and basal ganglia to that in the cerebellum were lower in the BD group than the normal group. The BD group had a higher ratio of the occipital cortex/the cerebellum than the control group, suggesting a decreased blood flow in the cerebellum. When I-123 IMP ratio in various areas to that in the occipital cortex was examined, both the BD and AD groups seemed to have a decreased blood flow over the whole cerebrum. The BD group had a lower I-123 IMP uptake in the thalamus and basal ganglia, and the AD group had it in the parietal cortex, relative to the occipital cortex. Blood flow patterns for BD were found to be different from those for AD. This suggests the difference in areas responsible for etiology between BD and AD. (N.K.)

  1. Deep vein thrombus formation induced by flow reduction in mice is determined by venous side branches.

    Science.gov (United States)

    Brandt, Moritz; Schönfelder, Tanja; Schwenk, Melanie; Becker, Christian; Jäckel, Sven; Reinhardt, Christoph; Stark, Konstantin; Massberg, Steffen; Münzel, Thomas; von Brühl, Marie-Luise; Wenzel, Philip

    2014-01-01

    Interaction between vascular wall abnormalities, inflammatory leukocytes, platelets, coagulation factors and hemorheology in the pathogenesis of deep vein thrombosis (DVT) is incompletely understood, requiring well defined animal models of human disease. We subjected male C57BL/6 mice to ligation of the inferior vena cava (IVC) as a flow reduction model to induce DVT. Thrombus size and weight were analyzed macroscopically and sonographically by B-mode, pulse wave (pw) Doppler and power Doppler imaging (PDI) using high frequency ultrasound. Thrombus size varied substantially between individual procedures and mice, irrespective of the flow reduction achieved by the ligature. Interestingly, PDI accurately predicted thrombus size in a very robust fashion (r2 = 0.9734, p thrombus weight (r2 = 0.5597, p thrombus formation. Occlusion of side branches prior to ligation of IVC did not increase thrombus size, probably due to patent side branches inaccessible to surgery. Venous side branches influence thrombus size in experimental DVT and might therefore prevent thrombus formation. This renders vessel anatomy and hemorheology important determinants in mouse models of DVT, which should be controlled for.

  2. Fast magnetic reconstruction of the portal vein with allogeneic blood vessels in canines.

    Science.gov (United States)

    Wang, Shan-Pei; Yan, Xiao-Peng; Xue, Fei; Dong, Ding-Hui; Zhang, Xu-Feng; Ma, Feng; Wang, Hao-Hua; Lv, Yi

    2015-06-01

    The resection and reconstruction of large vessels, including the portal vein, are frequently needed in tumor resection. Warm ischemia before reconstruction might have deleterious effects on the function of some vital organs and therefore, how to reconstruct the vessels quickly after resection is extremely important. The present study was to introduce a new type of magnetic compression anastomosis (MCA) device to establish a quick non-suture anastomosis of the portal vein after resection in canines. The new MCA device consists of a pair of titanium alloy and neodymium-ferrum-boron magnet (Ti-NdFeB) composite rings. The NdFeB magnetic ring as a core of the device was hermetically sealed inside the biomedical titanium alloy case. Twelve canines were divided into two groups: a MCA group in which the end-to-end anastomoses was made with a new device after resection in the portal vein and a traditional manual suture (TMS) group consisted of 6 canines. The anastomosis time, anastomotic patency and quality were investigated at week 24 postoperatively. The portal vein was reconstructed successfully in all of the animals and they all survived. The duration of portal vein anastomosis was significantly shorter in the MCA group than in the TMS group (8.16+/-1.25 vs 36.24+/-2.17 min, PNdFeB composite MCA device was applicable in reconstruction of large vessels after resection. This device was easy to use and the anastomosis was functionally better than the traditional sutured anastomosis.

  3. Gender differences in regional cerebral blood flow

    International Nuclear Information System (INIS)

    Gur, R.E.; Gur, R.C.

    1990-01-01

    Gender differences have been noted in neurobehavioral studies. The 133xenon inhalation method for measuring regional cerebral blood flow (rCBF) can contribute to the understanding of the neural basis of gender differences in brain function. Few studies have examined gender differences in rCBF. In studies of normal subjects, women have higher rates of CBF than men, and this is related to age. Usually by the sixth decade men and women have similar flow rates. Fewer studies on rCBF in schizophrenia have examined sex differences. The pattern of higher flows for females maintains, but its correlates with gender differences in clinical as well as other parameters of brain function remain to be examined

  4. Nonlinear interactions in renal blood flow regulation

    DEFF Research Database (Denmark)

    Marsh, Donald J.; Sosnovtseva, Olga; Chon, Ki H.

    2005-01-01

    We have developed a model of tubuloglomerular feedback (TGF) and the myogenic mechanism in afferent arterioles to understand how the two mechanisms are coupled. This paper presents the model. The tubular model predicts pressure, flow, and NaCl concentration as functions of time and tubular length...... hydrostatic pressure, and plasma flow rate. The arteriolar model predicts fraction of open K channels, intracellular Ca concentration (Ca-i), potential difference, rate of actin - myosin cross bridge formation, force of contraction, and length of elastic elements, and was solved for two arteriolar segments...... resistance and glomerular capillary pressure. The model couples TGF input to voltage-gated Ca channels. It predicts autoregulation of GFR and renal blood flow, matches experimental measures of tubular pressure and macula densa NaCl concentration, and predicts TGF-induced oscillations and a faster smaller...

  5. Effect of early adrenal vein ligation on blood pressure and catecholeamine fluctuation during laparoscopic adrenalectomy for pheochromocytoma.

    Science.gov (United States)

    Wu, Guojun; Zhang, Bo; Yu, Chuigong; Gao, Lei; Gao, Yang; Huang, Yi; Yu, Lei; Zhang, Geng; Yang, Lijun; Yuan, Jianlin

    2013-09-01

    To define whether previous control of the adrenal vein is a crucial procedure in laparoscopic adrenalectomy for pheochromocytoma. From January 2000 to December 2010, 114 patients with pheochromocytoma who underwent laparoscopic adrenalectomy through transperitoneal or retroperitoneal approach were included. The patients were divided into 2 groups randomly (group 1: dissection after ligation; group 2: dissection before ligation). Blood samples for the measurement of catecholamines levels using high performance liquid chromatography were taken at the following time points: t1, before anesthesia; t2, during manipulation-extraction of pheochromocytoma; t3, after removal of pheochromocytoma. The blood pressure fluctuation was recorded. Laparoscopic adrenalectomy was successfully performed on 113 patients with 1 elective open conversion because of dense peritumor adhesions. The operating time ranged from 80 to 150 minutes (mean 108, 102 in group 1, 110 in group 2). Mean blood loss ranged from 20 to 500 mL (mean 120 mL, 110 in group 1, 125 in group 2). The concentrations of plasma catecholamines between the 2 groups had no statistical differences. The blood pressure fluctuation incidence between the 2 groups had no marked difference. But the incidence increased with high functionary grade, and the difference was significant (P = .043). This study demonstrated that previous control of the adrenal vein was not a determinate factor in dealing with dangerous hypertension during laparoscopic adrenalectomies. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Regional cerebral blood flow in childhood headache

    International Nuclear Information System (INIS)

    Roach, E.S.; Stump, D.A.

    1989-01-01

    Regional cerebral blood flow (rCBF) was measured in 16 cranial regions in 23 children and adolescents with frequent headaches using the non-invasive Xenon-133 inhalation technique. Blood flow response to 5% carbon dioxide (CO2) was also determined in 21 patients, while response to 50% oxygen was measured in the two patients with hemoglobinopathy. Included were 10 patients with a clinical diagnosis of migraine, 4 with musculoskeletal headaches, and 3 with features of both types. Also studied were 2 patients with primary thrombocythemia, 2 patients with hemoglobinopathy and headaches, 1 patient with polycythemia, and 1 with headaches following trauma. With two exceptions, rCBF determinations were done during an asymptomatic period. Baseline rCBF values tended to be higher in these young patients than in young adults done in our laboratory. Localized reduction in the expected blood flow surge after CO2 inhalation, most often noted posteriorly, was seen in 8 of the 13 vascular headaches, but in none of the musculoskeletal headache group. Both patients with primary thrombocythemia had normal baseline flow values and altered responsiveness to CO2 similar to that seen in migraineurs; thus, the frequently reported headache and transient neurologic signs with primary thrombocythemia are probably not due to microvascular obstruction as previously suggested. These data support the concept of pediatric migraine as a disorder of vasomotor function and also add to our knowledge of normal rCBF values in younger patients. Demonstration of altered vasomotor reactivity to CO2 could prove helpful in children whose headache is atypical

  7. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... in our understanding of cerebral blood flow control have important implications for the development of new therapeutic approaches....

  8. Idiopathic Bilateral External Jugular Vein Thrombosis.

    Science.gov (United States)

    Hindi, Zakaria; Fadhel, Ehab

    2015-08-20

    Vein thrombosis is mainly determined by 3 factors, which constitute a triad called Virchow's triad: hypercoagulability, stasis, and endothelial injury. Venous thrombosis commonly occurs in the lower extremities since most of the blood resides there and flows against gravity. The veins of the lower extremities are dependent on intact valves and fully functional leg muscles. However, in case of valvular incompetency or muscular weakness, thrombosis and blood stasis will occur as a result. In contrast, the veins of the neck, specially the jugulars, have distensible walls which allow flexibility during respiration. In addition, the blood directly flows downward towards the heart. Nevertheless, many case reports mentioned the thrombosis of internal jugular veins and external jugular veins with identified risk factors. Jugular vein thrombosis has previously been associated in the literature with a variety of medical conditions, including malignancy. This report is of a case of idiopathic bilateral external jugular vein thrombosis in a 21 year-old male construction worker of Southeast Asian origin with no previous medical history who presented with bilateral facial puffiness of gradual onset over 1 month. Doppler ultrasound and computed tomography were used in the diagnosis. Further work-up showed no evidence of infection or neoplasia. The patient was eventually discharged on warfarin. The patient was assessed after 6 months and his symptoms had resolved completely. Bilateral idiopathic external jugular veins thrombosis is extremely rare and can be an indicator of early malignancy or hidden infection. While previous reports in the literature have associated jugular vein thrombosis with malignancy, the present case shows that external jugular vein thrombosis can also be found in persons without malignancy.

  9. Visualizing Veins With Near-Infrared Light to Facilitate Blood Withdrawal in Children

    NARCIS (Netherlands)

    Cuper, Natascha J.; Verdaasdonk, Rudolf M.; de Roode, Rowland; de Vooght, Karen M. K.; Viergever, Max A.; Kalkman, Cor J.; de Graaff, Jurgen C.

    Introduction. This study aims to evaluate for the first time the value of visualizing veins by a prototype of a near-infrared (NIR) vascular imaging system for venipuncture in children. Methods. An observational feasibility study of venipunctures in children (0-6 years) attending the clinical

  10. Hepatic portal vein cannulation for infusion and blood sampling in freely moving rats

    NARCIS (Netherlands)

    Strubbe, J.H.; Bruggink, J.E; Steffens, A.B

    1999-01-01

    Chronic portal vein cannulation in the rat is an important technique to study secretory rates of hormones from the endocrine pancreas. Moreover, it can be used for studying the effects of enteric hormones and pharmaca on behavioral and physiological processes. This article contains an extensive

  11. Changes of blood levels of LPO, SOD and GSH-Px after endovenous laser treatment of varicose greater saphenous vein

    International Nuclear Information System (INIS)

    Han Li'na; Gu Ying; Liu Fanguang

    2004-01-01

    Objective: To investigate the changes of the blood levels of lipid peroxide (LPO), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) after treatment of varicose greater saphenous vein with either endovenous laser or conventional surgery (high ligation plus stripping). Methods: Thirty-seven patients with varicose greater saphenous vein were treated with endovenous laser and another 33 patients were treated with conventional surgery. Levels of LPO (serum, with TBA fluorescein), SOD (whole blood, with RIA) and GSH-Px (whole blood, with direct DTNB) were determined in these patients both before and 1, 3, 5, 7, 10, 15 days after treatment. Levels in 30 controls were also measured. Results: The levels of LPO were higher and levels of SOD, GSH-Px lower in the patients than those in the controls. After either form of therapy, the levels LPO rose and levels of SOD, GSH-Px dropped immediately but gradually approached the control values by the 15 th day (slower with SOD and GSH-Px). However, the early increase of LPO levels were less and recovery sooner in the group of patients treated with laser. Conclusion: Changes of levels of LPO, SOD and GSH-Px were closely related to the degree of stress and recovery condition after the treatment

  12. Regional cerebral blood flow in diabetic patients

    International Nuclear Information System (INIS)

    Nagamachi, Shigeki; Ono, Shinnichi; Nishikawa, Takushi

    1993-01-01

    N-isopropyl-p- 123 I-iodoamphetamine (IMP) was used to quantify the regional cerebral blood flow (r-CBF) in 11 diabetic patients (average age; 67.9 years) and 12 non-diabetic subjects (average age; 67.4 years), none of whom had (cerebrovascular disease (CVD) on CT studies. A reference sampling method by continuous arterial blood sampling was used to quantify r-CBF. There were no significant differences in physiological or laboratory data between diabetic and non-diabetic groups except for fasting plasma glucose and HbA 1c levels. The average of r-CBF in each region of cerebrum and cerebellum was significantly lower in diabetic group than that in the control group (p<0.01). These observations show that r-CBF of diabetic patients is reduced, even in the absence of findings of CVD on a CT study. (author)

  13. Blood flow in healed and inflamed periodontal tissues of dogs

    Energy Technology Data Exchange (ETDEWEB)

    Hock, J.M.; Kim, S.

    1987-01-01

    The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p<0.05) lower in non-inflamed healed gingiva (32.1 +- 2.7 ml/min/100 g) than in inflamed gingiva (46.1 +- 5.3 ml/min/100 g). No differences in the blood flow of the alveolar bone underlying inflamed or non-inflamed gingiva were present. In the second experiment, the right mandibular teeth of 5 dogs were treated to resolve periodontitis while teeth in the other quadrants were ligated for 4, 10 or 12 wk. The duration of ligation did not alter blood flow. Gingival blood flow around ligated maxillary and mandibular teeth was comparable and approximately 54% higher than around non-ligated teeth (p<0.03). The difference in blood flow between gingiva with G.I.>1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow.

  14. Role of blood flow and blood flow modifiers in clinical hyperthermia therapy

    International Nuclear Information System (INIS)

    Olch, A.J.

    1986-01-01

    A quantitative assessment of the effect of localized magnetic-loop hyperthermia on blood flow was performed on 12 patients (19 tumor studies) using the Xenon-133 clearance method. After it was discovered that blood flow in most of the tumors increased in response to needle injection, a physiologically based, one compartment model was developed that included both a hyperemic (transient) and a steady state component. In the tumors of six patients, increases in blood flow induced by heat were also observed. The same model was used to describe the measured clearance data for both types of hyperemic response. The ability of tumor vessels to respond dynamically to stress and the degree of response may be predictive of tumor heating efficiency and subsequent therapeutic response. Many tumors treated by hyperthermia, therefore, do not reach therapeutic temperatures (42 0 C). One explanation for this may be that some tumors react to thermal stress in a manner similar to normal tissues; i.e., they increase blood flow during hyperthermia in order to dissipate heat. Higher temperatures might be achieved in these heat-resistant tumors by administering vasoconstrictive agents in an effort to reduce blood flow. In the second part of this research study, the extent to which pharmacologic inhibition of local blood flow might allow higher temperatures to develop in normal muscles exposed to localized radiofrequency hyperthermia was determined. It was found that the local muscle temperature rise could be increased by at least 90% in dogs and rabbits with the use of a local vasoconstrictive drug

  15. Cerebral blood flow and metabolism during sleep

    DEFF Research Database (Denmark)

    Madsen, Peter Lund; Vorstrup, S

    1991-01-01

    A review of the current literature regarding sleep-induced changes in cerebral blood flow (CBF) and cerebral metabolic rate (CMR) is presented. Early investigations have led to the notion that dreamless sleep was characterized by global values of CBF and CMR practically at the level of wakefulness......, while rapid eye movement (REM) sleep (dream sleep) was a state characterized by a dramatically increased level of CBF and possibly also of CMR. However, recent investigations firmly contradict this notion. Investigations on CBF and CMR performed during non-REM sleep, taking the effect of different...... current state identify the physiological processes involved in sleep or the physiological role of sleep....

  16. Portal vein thrombosis.

    Science.gov (United States)

    Chawla, Yogesh K; Bodh, Vijay

    2015-03-01

    Portal vein thrombosis is an important cause of portal hypertension. PVT occurs in association with cirrhosis or as a result of malignant invasion by hepatocellular carcinoma or even in the absence of associated liver disease. With the current research into its genesis, majority now have an underlying prothrombotic state detectable. Endothelial activation and stagnant portal blood flow also contribute to formation of the thrombus. Acute non-cirrhotic PVT, chronic PVT (EHPVO), and portal vein thrombosis in cirrhosis are the three main variants of portal vein thrombosis with varying etiological factors and variability in presentation and management. Procoagulant state should be actively investigated. Anticoagulation is the mainstay of therapy for acute non-cirrhotic PVT, with supporting evidence for its use in cirrhotic population as well. Chronic PVT (EHPVO) on the other hand requires the management of portal hypertension as such and with role for anticoagulation in the setting of underlying prothrombotic state, however data is awaited in those with no underlying prothrombotic states. TIPS and liver transplant may be feasible even in the setting of PVT however proper selection of candidates and type of surgery is warranted. Thrombolysis and thrombectomy have some role. TARE is a new modality for management of HCC with portal vein invasion.

  17. Cerebral blood flow and metabolism during exercise: implications for fatigue.

    Science.gov (United States)

    Secher, Neils H; Seifert, Thomas; Van Lieshout, Johannes J

    2008-01-01

    During exercise: the Kety-Schmidt-determined cerebral blood flow (CBF) does not change because the jugular vein is collapsed in the upright position. In contrast, when CBF is evaluated by (133)Xe clearance, by flow in the internal carotid artery, or by flow velocity in basal cerebral arteries, a approximately 25% increase is detected with a parallel increase in metabolism. During activation, an increase in cerebral O(2) supply is required because there is no capillary recruitment within the brain and increased metabolism becomes dependent on an enhanced gradient for oxygen diffusion. During maximal whole body exercise, however, cerebral oxygenation decreases because of eventual arterial desaturation and marked hyperventilation-related hypocapnia of consequence for CBF. Reduced cerebral oxygenation affects recruitment of motor units, and supplemental O(2) enhances cerebral oxygenation and work capacity without effects on muscle oxygenation. Also, the work of breathing and the increasing temperature of the brain during exercise are of importance for the development of so-called central fatigue. During prolonged exercise, the perceived exertion is related to accumulation of ammonia in the brain, and data support the theory that glycogen depletion in astrocytes limits the ability of the brain to accelerate its metabolism during activation. The release of interleukin-6 from the brain when exercise is prolonged may represent a signaling pathway in matching the metabolic response of the brain. Preliminary data suggest a coupling between the circulatory and metabolic perturbations in the brain during strenuous exercise and the ability of the brain to access slow-twitch muscle fiber populations.

  18. Glial and neuronal control of brain blood flow

    DEFF Research Database (Denmark)

    Attwell, David; Buchan, Alastair M; Charpak, Serge

    2010-01-01

    Blood flow in the brain is regulated by neurons and astrocytes. Knowledge of how these cells control blood flow is crucial for understanding how neural computation is powered, for interpreting functional imaging scans of brains, and for developing treatments for neurological disorders. It is now...... recognized that neurotransmitter-mediated signalling has a key role in regulating cerebral blood flow, that much of this control is mediated by astrocytes, that oxygen modulates blood flow regulation, and that blood flow may be controlled by capillaries as well as by arterioles. These conceptual shifts...

  19. The effect of sympathectomy on bone blood flow in man

    International Nuclear Information System (INIS)

    Lahtinen, T.; Alhava, E.M.; Hyoedynmaa, S.; Hendolin, H.; Oksala, I.

    1982-01-01

    The effect of lumbar sympathectomy on bone blood flow was measured in seven patients with a Xe-133 washout method. On the third postoperative day there was a significant increase of blood flow in the proximal femur and a slight increase in the proximal tibia. Two months after the operation blood flow in the proximal part of the femur was no more significantly increased but in the proximal tibia there was a significant increase. The study suggests that the positive effect of sympathectomy on bone blood flow may be of value in cases where the increase of blood flow to peripheral bones is required

  20. Blood flow in healed and inflamed periodontal tissues of dogs

    International Nuclear Information System (INIS)

    Hock, J.M.; Kim, S.

    1987-01-01

    The objectives of this study were to determine if increased blood flow associated with gingivitis would decrease following resolution of gingival inflammation in dogs with periodontitis; if increased blood flow in inflamed gingiva was associated with changes in the blood flow of alveolar bone, and if blood flow in gingiva and alveolar bone increased if periodontitis was reactivated by ligating teeth. Regional blood flow was measured in dogs with pre-existing periodontitis, using radioisotope-labelled, plastic microspheres. In the first experiment on 4 adult Beagle dogs, teeth in the left jaws were treated to resolve the periodontitis, while teeth in the right jaws were not treated. Gingival and bone blood flow were measured after 12 wk. Blood flow was significantly (p 1 and gingiva with G.I.<2 was significant (p<0.04). Blood flow in bone was not altered by changes in the inflammatory status of the overlying gingiva. The findings suggest that changes in blood flow associated with inflammation are reversible and that blood flow alveolar bone is regulated independently of gingival blood flow. (author)

  1. A Computational Framework to Optimize Subject-Specific Hemodialysis Blood Flow Rate to Prevent Intimal Hyperplasia

    Science.gov (United States)

    Mahmoudzadeh, Javid; Wlodarczyk, Marta; Cassel, Kevin

    2017-11-01

    Development of excessive intimal hyperplasia (IH) in the cephalic vein of renal failure patients who receive chronic hemodialysis treatment results in vascular access failure and multiple treatment complications. Specifically, cephalic arch stenosis (CAS) is known to exacerbate hypertensive blood pressure, thrombosis, and subsequent cardiovascular incidents that would necessitate costly interventional procedures with low success rates. It has been hypothesized that excessive blood flow rate post access maturation which strongly violates the venous homeostasis is the main hemodynamic factor that orchestrates the onset and development of CAS. In this article, a computational framework based on a strong coupling of computational fluid dynamics (CFD) and shape optimization is proposed that aims to identify the effective blood flow rate on a patient-specific basis that avoids the onset of CAS while providing the adequate blood flow rate required to facilitate hemodialysis. This effective flow rate can be achieved through implementation of Miller's surgical banding method after the maturation of the arteriovenous fistula and is rooted in the relaxation of wall stresses back to a homeostatic target value. The results are indicative that this optimized hemodialysis blood flow rate is, in fact, a subject-specific value that can be assessed post vascular access maturation and prior to the initiation of chronic hemodialysis treatment as a mitigative action against CAS-related access failure. This computational technology can be employed for individualized dialysis treatment.

  2. Semiquantifying regional cerebral blood flow by dynamic CT scanning

    International Nuclear Information System (INIS)

    Takeuchi, Totaro; Kasahara, Eishi; Takahashi, Eriko; Kojima, Seiichi; Ogawa, Haruhiko; Suzuki, Keiko; Miyamae, Tatsuya; Yamazaki, Setsuo.

    1990-01-01

    The study was undertaken to evaluate the semi-quantitative significance of the absolute value obtained by calculating the regional cerebral blood flow index (rCBFI) from dynamic CT in comparison with SPECT. rCBFI was calculated from mean transit time (MTT) and blood capacity index (BCI) obtained by rapidly infusing 50 ml of Omnipurk into the elbow vein by the use of Hitachi's W-600. [rCBFI=BCI/MTT unit/sec (U/S)] measurment of the rCBF by SPECT was made according to the semi-quantitative method by Matsuda et al. by the use of SHIMADZU's improved type HEADTOME SET-050 with rapid infusion of 123 I-IMP in 3.5 m Ci from the elbow vein. Patients in whom no abnormality was observed in the cardiopulmonary function were enrolled as subjects. The rCBFI in each intracranial site was calculated from dynamic CT in 10 normal adults (aged 35-60, averaging 46.7) as subjects and compared with the rCBF obtained from SPECT in the same cases and same site. Comparative investigation was made similarly between rCBFI and rCBF regarding 10 patients with tracranial diseases (age 29-65, averaging 51.2). The mean rCBFIs in the normal adults obtained from dynamic CT were 1.15±0.18 U/S in the frontal lobar cortex, 1.28±0.19 U/S in the temporal lobar cortex, 1.43±0.1 U/S in the occipital lobar cortex, 1.27±0.2 U/S in the basal ganglia region and 0.43±0.1 U/S in the white matter. On the other hand, the mean rCBFs by SPECT were 47.36±3.93 ml/100 g/min, 55.19±2.22 ml/100 g/min, 61.92±5.42 ml/100 g/min, 54.38±3.51 ml/100 g/min and 38.68±6.18 ml/100 g/min, respectively. Positive correlation was observed between rCBFIs and rCBFs of 10 normal adults and 10 patients with intracranial disease, totalling 20 cases (r=0.79, P<0.005). The rCBFI by dynamic CT has a correlation with the rCBF by SPECT, suggesting the possibility of its evaluation as an absolute value, though semi-quantitatively. (author)

  3. [Autologous transfusion of UV-irradiated blood in the complex treatment of children with dysplasia of deep veins of the extremities].

    Science.gov (United States)

    Levanovich, V V; Kupatadze, D D; Endzhibadze, Iu G; Nabokov, V V; Mazurova, E V; Ivanov, A P; Chirovich, M

    1991-02-01

    Under examination there were 12 patients aged from 5 till 14 years. An investigation of hemostatic potential of blood in the diseased extremity and peripheral blood was performed. A mosaic character of blood coagulative alterations in this category of patients was detected. Autotransfusion of UV-irradiated blood is a pathogenetically grounded and accessible method of correction of hemocoagulation and may be included in the complex treatment of patients with dysplasia of the profound veins of lower extremities.

  4. Remodelling of choroidal blood flow in radiation choroidopathy

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Hideo; Muraoka, Kanemitsu; Takahashi, Kyoichi; Sutoh, Noriko [Gunma Univ., Maebashi (Japan). School of Medicine

    1997-02-01

    Two males, aged 68 and 34 years each, presented with radiation retinopathy. One had received radiation therapy to the whole brain for intracranial metastasis of lung carcinoma 29 months before. The other underwent surgery and radiation for melanoma of the upper eyelid 15 years before. When examined by indocyanine green angiography. both cases showed vasoocclusive changes in the choroid involving the choriocapillaris and major vessels in the affected fundus area. In one eye with severe retinal vascular lesions in the superior temporal quadrant, the vortex vein in the quadrant had obliterated. The venous blood in this quadrant was drained into the inferior temporal vortex vein crossing the presumed watershed zone temporal to the macula. Collaterals had formed between choroidal arteries and between choroidal veins. These cases illustrate that choroidal vascular lesions may be present in radiation retinopathy, that the former may be more pronounced than the latter and that choroidal vessels may undergo extensive remodelling to compensate for the disturbed choroidal circulation. (author)

  5. Remodelling of choroidal blood flow in radiation choroidopathy

    International Nuclear Information System (INIS)

    Kobayashi, Hideo; Muraoka, Kanemitsu; Takahashi, Kyoichi; Sutoh, Noriko

    1997-01-01

    Two males, aged 68 and 34 years each, presented with radiation retinopathy. One had received radiation therapy to the whole brain for intracranial metastasis of lung carcinoma 29 months before. The other underwent surgery and radiation for melanoma of the upper eyelid 15 years before. When examined by indocyanine green angiography. both cases showed vasoocclusive changes in the choroid involving the choriocapillaris and major vessels in the affected fundus area. In one eye with severe retinal vascular lesions in the superior temporal quadrant, the vortex vein in the quadrant had obliterated. The venous blood in this quadrant was drained into the inferior temporal vortex vein crossing the presumed watershed zone temporal to the macula. Collaterals had formed between choroidal arteries and between choroidal veins. These cases illustrate that choroidal vascular lesions may be present in radiation retinopathy, that the former may be more pronounced than the latter and that choroidal vessels may undergo extensive remodelling to compensate for the disturbed choroidal circulation. (author)

  6. Regional cerebral blood flow in schizophrenics

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, J.; Ohta, Y.; Nakane, Y.; Mori, H.; Hirota, N.; Yonekura, M.

    1987-01-01

    The present study on schizophrenics dealt with the relationship of regional cerebral blood flow (rCBF) to age, disease duration, and treatment length with chlorpromazine hydrochloride (CPZ). Regional cerebral blood flow in 28 cerebral regions of interest was measured by iv injection of /sup 133/X in 54 schizophrenic patients and 39 healthy volunteers. Neither age nor dosage of CPZ significantly influenced rCBF. All patients, including 11 treated for a short period of time (6 months or less), were characterized by having a decreased rCBF over the whole cerebrum. Thirty-four patients treated for a long period of time (2 years or more) had a varied rCBF distribution in the left hemisphere, with the most predominant feature being the decrease in rCBF in the frontal lobe (i.e., hypofrontality); however, there was no linear correlation between rCBF and disease duration. A decreased rCBE in the right occipital region was seen in patients with paranoid schizophrenia, suggesting that manifestations of symptoms may depend on disturbed regions. These results suggest that cerebral dysfunction in schizophrenic patients may not be restricted to the frontal lobe, but cover the whole cerebrum, and that nonuniform dysfunction in various regions of the cerebrum, including the frontal lobe, may be involved in manifestations of symptoms.

  7. Regional cerebral blood flow in schizophrenics

    International Nuclear Information System (INIS)

    Uchino, Jun; Ohta, Yasuyuki; Nakane, Yoshibumi; Mori, Hiroyuki; Hirota, Noriyoshi; Yonekura, Masahiro.

    1987-01-01

    The present study on schizophrenics dealt with the relationship of regional cerebral blood flow (rCBF) to age, disease duration, and treatment length with chlorpromazine hydrochloride (CPZ). Regional cerebral blood flow in 28 cerebral regions of interest was measured by iv injection of X-133 in 54 schizophrenic patients and 39 healthy volunteers. Neither age nor dosage of CPZ significantly influenced rCBF. All patients, including 11 treated for a short period of time (6 months or less), were characterized by having a decreased rCBF over the whole cerebrum. Thirty-four patients treated for a long period of time (2 years or more) had a varied rCBF distribution in the left hemisphere, with the most predominant feature being the decrease in rCBF in the frontal lobe (i.e., ''hypofrontality''); however, there was no linear correlation between rCBF and disease duration. A decreased rCBE in the right occipital region was seen in patients with paranoid schizophrenia, suggesting that manifestations of symptoms may depend on disturbed regions. These results suggest that cerebral dysfunction in schizophrenic patients may not be restricted to the frontal lobe, but cover the whole cerebrum, and that nonuniform dysfunction in various regions of the cerebrum, including the frontal lobe, may be involved in manifestations of symptoms. (Namekawa, K.)

  8. Regional blood flow in experimental myositis ossificans

    International Nuclear Information System (INIS)

    Hierton, C.

    1983-01-01

    In a recent model for heterotopic bone formation, muscular oedema, swelling and necrosis is seen in the quadriceps muscle of rabbit hind limbs immobilized for at least 2 weeks when, from the second week, the immobilized limb is subjected to dayly forcible mobilization lasting about 5 min. According to this model, heterotopic calcification develops gradually from the second week of forcible mobilization and is located in the vastus intermedius region. Between the fourth and fifth week of immobilization and forcible mobilization, heterotopic bone formation is seen in virtually all cases. The histological findings are similar to those in human ectopic bone formation. In the present investigation the labelled microsphere technique was used to study the regional blood flow effects in the early development of myositis ossificans with this model. The results are quite different from those reported by other investigators on immobilization alone and point to a causal relation between regional blood flow and forcible mobilization of the immobilized rabbit hind limp. Prostaglandins as mediators between the traumatic inflammation, a part of the circulatory effects observed and the induction of a new bone is suggested. (author)

  9. Comparison of fractional flow reserve of composite Y-grafts with saphenous vein or right internal thoracic arteries.

    Science.gov (United States)

    Glineur, David; Boodhwani, Munir; Poncelet, Alain; De Kerchove, Laurent; Etienne, Pierre Yves; Noirhomme, Philippe; Deceuninck, Paul; Michel, Xavier; El Khoury, Gebrine; Hanet, Claude

    2010-09-01

    Composite Y-grafts, using the left internal thoracic artery as the inflow, allow a more efficient use of conduits without the need to touch a diseased ascending aorta. Among other conduits, the saphenous vein graft may be an alternative to the radial artery in elderly patients. We evaluated the hemodynamic characteristics of 17 composite Y-grafts made with the left internal thoracic artery anastomosed to the left anterior descending coronary artery in all cases and with either the free right internal thoracic artery (RITA group, n = 10) or a saphenous vein graft (SVG group, n = 7) implanted proximally to the left internal thoracic artery and distally to the circumflex territory 6 months after the operation. At baseline, the pressure gradient measured with a 0.014-inch pressure wire was minimal between the aorta and the internal thoracic artery stem (2 +/- 1 mm Hg), the internal thoracic artery and left anterior descending (4 +/- 2 mm Hg), the internal thoracic artery and left circumflex (3 +/- 1 mm Hg), and the saphenous vein graft and left circumflex (2 +/- 2 mm Hg). During hyperemia induced by adenosine, the pressure gradient increased significantly to 6 +/- 2 mm Hg in the internal thoracic artery stem, 9 +/- 4 mm Hg in the internal thoracic artery and left anterior descending artery, 9 +/- 3 mm Hg in the internal thoracic artery and left circumflex, and 7 +/- 4 mm Hg in the saphenous vein graft and left circumflex. Fractional flow reserve was 0.94 +/- 0.02 in internal thoracic artery stem, 0.90 +/- 0.04 mm Hg in the internal thoracic artery and left anterior descending, 0.91 +/- 0.03 mm Hg in the internal thoracic artery and left circumflex, and 0.92 +/- 0.06 mm Hg in the saphenous vein graft and left circumflex. No difference between the two types of composite Y-grafts was observed for pressure gradients or fractional flow reserve measured in internal thoracic artery stem or in distal branches. Composite Y-grafts with saphenous vein or right internal thoracic

  10. Posture changes and subfoveal choroidal blood flow.

    Science.gov (United States)

    Longo, Antonio; Geiser, Martial H; Riva, Charles E

    2004-02-01

    To evaluate the effect of posture change on subfoveal choroidal blood flow (ChBF) in normal volunteers. The pulsatile, nonpulsatile, and mean ChBF were measured with laser Doppler flowmetry in 11 healthy volunteers with a mean age of 32 +/- 13 (SD) years. The posture of the subjects was changed from standing (90 degrees ), to supine (-8 degrees ), and back to standing, with a mechanically driven table. During the whole experimental procedure, ChBF and heart rate (HR) were continuously recorded. After 30 seconds in standing position, the subjects were tilted to supine during approximately 30 seconds. They remained in this position for approximately 2 minutes, after which they were tilted back to the standing position (recovery), where they remained for another approximately 2 minutes. Systemic brachial artery blood pressure (BP) was measured in the baseline, supine, and recovery positions. This procedure was repeated to measure the intraocular pressure (IOP) at the different postures. Mean BP did not change significantly throughout the experimental procedure. As the body was tilted from standing to supine, HR decreased by 16% (P blood velocity. Based on previously reported experimental data that indicate that the ocular perfusion pressure increases less than predicted by purely hydrostatic considerations when the body is tilted from the standing to the supine position, the observed increase in ChBF suggests a passive response of the choroidal circulation to the posture change.

  11. Modeling microcirculatory blood flow: current state and future perspectives.

    Science.gov (United States)

    Gompper, Gerhard; Fedosov, Dmitry A

    2016-01-01

    Microvascular blood flow determines a number of important physiological processes of an organism in health and disease. Therefore, a detailed understanding of microvascular blood flow would significantly advance biophysical and biomedical research and its applications. Current developments in modeling of microcirculatory blood flow already allow to go beyond available experimental measurements and have a large potential to elucidate blood flow behavior in normal and diseased microvascular networks. There exist detailed models of blood flow on a single cell level as well as simplified models of the flow through microcirculatory networks, which are reviewed and discussed here. The combination of these models provides promising prospects for better understanding of blood flow behavior and transport properties locally as well as globally within large microvascular networks. © 2015 Wiley Periodicals, Inc.

  12. A simple method for measurement of cerebral blood flow using 123I-IMP SPECT with calibrated standard input function by one point blood sampling. Validation of calibration by one point venous blood sampling as a substitute for arterial blood sampling

    International Nuclear Information System (INIS)

    Ito, Hiroshi; Akaizawa, Takashi; Goto, Ryoui

    1994-01-01

    In a simplified method for measurement of cerebral blood flow using one 123 I-IMP SPECT scan and one point arterial blood sampling (Autoradiography method), input function is obtained by calibrating a standard input function by one point arterial blood sampling. A purpose of this study is validation of calibration by one point venous blood sampling as a substitute for one point arterial blood sampling. After intravenous infusion of 123 I-IMP, frequent arterial and venous blood sampling were simultaneously performed on 12 patients of CNS disease without any heart and lung disease and 5 normal volunteers. The radioactivity ratio of venous whole blood which obtained from cutaneous cubital vein to arterial whole blood were 0.76±0.08, 0.80±0.05, 0.81±0.06, 0.83±0.11 at 10, 20, 30, 50 min after 123 I-IMP infusion, respectively. The venous blood radioactivities were always 20% lower than those of arterial blood radioactivity during 50 min. However, the ratio which obtained from cutaneous dorsal hand vein to artery were 0.93±0.02, 0.94±0.05, 0.98±0.04, 0.98±0.03, at 10, 20, 30, 50 min after 123 I-IMP infusion, respectively. The venous blood radioactivity was consistent with artery. These indicate that arterio-venous difference of radioactivity in a peripheral cutaneous vein like a dorsal hand vein is minimal due to arteriovenous shunt in palm. Therefore, a substitution by blood sampling from cutaneous dorsal hand vein for artery will be possible. Optimized time for venous blood sampling evaluated by error analysis was 20 min after 123 I-IMP infusion, which is 10 min later than that of arterial blood sampling. (author)

  13. Low cerebral blood flow in hypotensive perinatal distress

    DEFF Research Database (Denmark)

    Lou, H C; Lassen, N A; Friis-Hansen, B

    1977-01-01

    was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays...... a crucial role in the development of perinatal hypoxic brain injury....

  14. Capillary pericytes regulate cerebral blood flow in health and disease

    DEFF Research Database (Denmark)

    Hall, Catherine N; Reynell, Clare; Gesslein, Bodil

    2014-01-01

    Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate t...

  15. Modified Beer-Lambert law for blood flow.

    Science.gov (United States)

    Baker, Wesley B; Parthasarathy, Ashwin B; Busch, David R; Mesquita, Rickson C; Greenberg, Joel H; Yodh, A G

    2014-11-01

    We develop and validate a Modified Beer-Lambert law for blood flow based on diffuse correlation spectroscopy (DCS) measurements. The new formulation enables blood flow monitoring from temporal intensity autocorrelation function data taken at single or multiple delay-times. Consequentially, the speed of the optical blood flow measurement can be substantially increased. The scheme facilitates blood flow monitoring of highly scattering tissues in geometries wherein light propagation is diffusive or non-diffusive, and it is particularly well-suited for utilization with pressure measurement paradigms that employ differential flow signals to reduce contributions of superficial tissues.

  16. Computational model on pulsatile flow of blood through a tapered ...

    Indian Academy of Sciences (India)

    S PRIYADHARSHINI

    2017-11-02

    Nov 2, 2017 ... It is pertinent to note that the magnitudes of flow resistance are higher in the case of ... mathematical model on non-Newtonian flow of blood through a ..... The important predictions of the present investigation are enumerating the .... drug carriers for targeted drug delivery, reducing blood flow at the time of ...

  17. Preservation of renal blood flow by the antioxidant EUK-134 in LPS-treated pigs.

    Science.gov (United States)

    Magder, Sheldon; Parthenis, Dimitrios G; Ghouleh, Imad Al

    2015-03-25

    Sepsis is associated with an increase in reactive oxygen species (ROS), however, the precise role of ROS in the septic process remains unknown. We hypothesized that treatment with EUK-134 (manganese-3-methoxy N,N'-bis(salicyclidene)ethylene-diamine chloride), a compound with superoxide dismutase and catalase activity, attenuates the vascular manifestations of sepsis in vivo. Pigs were instrumented to measure cardiac output and blood flow in renal, superior mesenteric and femoral arteries, and portal vein. Animals were treated with saline (control), lipopolysaccharide (LPS; 10 µg·kg-1·h-1), EUK-134, or EUK-134 plus LPS. Results show that an LPS-induced increase in pulmonary artery pressure (PAP) as well as a trend towards lower blood pressure (BP) were both attenuated by EUK-134. Renal blood flow decreased with LPS whereas superior mesenteric, portal and femoral flows did not change. Importantly, EUK-134 decreased the LPS-induced fall in renal blood flow and this was associated with a corresponding decrease in LPS-induced protein nitrotyrosinylation in the kidney. PO2, pH, base excess and systemic vascular resistance fell with LPS and were unaltered by EUK-134. EUK-134 also had no effect on LPS-associated increase in CO. Interestingly, EUK-134 alone resulted in higher CO, BP, PAP, mean circulatory filling pressure, and portal flow than controls. Taken together, these data support a protective role for EUK-134 in the renal circulation in sepsis.

  18. Small gliomas; Metabolism and blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Tamura, Masaru; Shibasaki, Takashi; Horikoshi, Satoru; Ono, Nobuo; Zama, Akira; Kakegawa, Tohru; Ishiuchi, Shogo [Gunma Univ., Maebashi (Japan). School of Medicine

    1994-02-01

    Eight patients with small gliomas (6 low-grade and 2 high-grade) localized in a single gyrus or less than 2 cm diameter were investigated using positron tomography and single photon emission computed tomography. All three tumors examined demonstrated hypermetabolism of amino acids. High-grade gliomas demonstrated hypermetabolism of glucose and high blood flow, but normal or low oxygen metabolism. High-grade gliomas also showed accumulation of [sup 201]Tl chloride and high or low accumulation of [sup 123]I-isopropyl iodoamphetamine. These indications allow preoperative diagnosis of the malignancy of small gliomas, which is important because small gliomas with high-grade malignancy need more extensive removal and adjuvant therapy. (author).

  19. Cerebral blood flow in normal pressure hydrocephalus

    International Nuclear Information System (INIS)

    Mamo, H.L.; Meric, P.C.; Ponsin, J.C.; Rey, A.C.; Luft, A.G.; Seylaz, J.A.

    1987-01-01

    A xenon-133 method was used to measure cerebral blood flow (CBF) before and after cerebrospinal fluid (CSF) removal in patients with normal pressure hydrocephalus (NPH). Preliminary results suggested that shunting should be performed on patients whose CBF increased after CSF removal. There was a significant increase in CBF in patients with NPH, which was confirmed by the favorable outcome of 88% of patients shunted. The majority of patients with senile and presenile dementia showed a decrease or no change in CBF after CSF removal. It is suggested that although changes in CBF and clinical symptoms of NPH may have the same cause, i.e., changes in the cerebral intraparenchymal pressure, there is no simple direct relation between these two events. The mechanism underlying the loss of autoregulation observed in NPH is also discussed

  20. Cerebral blood flow variations in CNS lupus

    International Nuclear Information System (INIS)

    Kushner, M.J.; Tobin, M.; Fazekas, F.; Chawluk, J.; Jamieson, D.; Freundlich, B.; Grenell, S.; Freemen, L.; Reivich, M.

    1990-01-01

    We studied the patterns of cerebral blood flow (CBF), over time, in patients with systemic lupus erythematosus and varying neurologic manifestations including headache, stroke, psychosis, and encephalopathy. For 20 paired xenon-133 CBF measurements, CBF was normal during CNS remissions, regardless of the symptoms. CBF was significantly depressed during CNS exacerbations. The magnitude of change in CBF varied with the neurologic syndrome. CBF was least affected in patients with nonspecific symptoms such as headache or malaise, whereas patients with encephalopathy or psychosis exhibited the greatest reductions in CBF. In 1 patient with affective psychosis, without clinical or CT evidence of cerebral ischemia, serial SPECT studies showed resolution of multifocal cerebral perfusion defects which paralleled clinical recovery

  1. Quantitative measurement of the cerebral blood flow

    International Nuclear Information System (INIS)

    Houdart, R.; Mamo, H.; Meric, P.; Seylaz, J.

    1976-01-01

    The value of the cerebral blood flow measurement (CBF) is outlined, its limits are defined and some future prospects discussed. The xenon 133 brain clearance study is at present the most accurate quantitative method to evaluate the CBF in different regions of the brain simultaneously. The method and the progress it has led to in the physiological, physiopathological and therapeutic fields are described. The major disadvantage of the method is shown to be the need to puncture the internal carotid for each measurement. Prospects are discussed concerning methods derived from the same general principle but using a simpler, non-traumatic way to introduce the radio-tracer, either by breathing into the lungs or intraveinously [fr

  2. Dopexamine increases internal mammary artery blood flow following coronary artery bypass grafting.

    LENUS (Irish Health Repository)

    Flynn, Michael J

    2012-02-03

    OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have previously been localized to human left ventricle. METHODS: Twenty-six American Society of Anaesthesiology class 2-3 elective coronary artery bypass graft patients who did not require inotropic support on separation from cardiopulmonary bypass (CPB) were studied. According to a randomized allocation patients received either dopexamine (1 microg\\/kg per min) or placebo (saline) by intravenous infusion for 15 min. Immediately prior to and at 5,10 and 15 min of infusion, blood flow through the internal mammary and vein grafts (Transit time flow probes, Transonic Ltd.), heart rate, cardiac index, mean arterial pressure and pulmonary haemodynamics were noted. The data were analysed using multivariate analysis of variance. RESULTS: Low-dose dopexamine (1 microg\\/kg per min) caused a significant increase in mammary graft blood flow compared to placebo at 15 min of infusion (P=0.028, dopexamine group left internal mammary artery (LIMA) flow of 43.3+\\/-14.2 ml\\/min, placebo group LIMA flow at 26.1+\\/-16.3 ml\\/min). Dopexamine recipients demonstrated a non-significant trend to increased saphenous vein graft flow (P=0.059). Increased heart rate was the only haemodynamic change induced by dopexamine (P=0.004, dopexamine group at 85.2+\\/-9.6 beats\\/min and placebo group at 71.1+\\/-7.6 beats\\/min after 15 min of infusion). CONCLUSION: This study demonstrates that administration of dopexamine (1 microg\\/kg per min) was associated with a significant increase in internal mammary artery graft blood flow with mild increase in heart rate being the only haemodynamic change. Low-dose dopexamine may

  3. Randomized trial of tourniquet vs blood pressure cuff for target vein dilation in ultrasound-guided peripheral intravenous access.

    Science.gov (United States)

    Nelson, Drew; Jeanmonod, Rebecca; Jeanmonod, Donald

    2014-07-01

    Ten percent of the time, peripheral intravenous access (PIV) is not obtained in 2 attempts in the emergency department. Typically, a tourniquet is used to dilate the target vein; but recent research showed that a blood pressure (BP) cuff improves dilation, which may translate to increased PIV success. We sought to determine if there is improved success in obtaining ultrasound-guided PIV using a BP cuff vs a tourniquet in "difficult stick" patients. This is a prospective, randomized, single-blinded trial. Adult patients requiring PIV with at least 2 prior failed attempts were enrolled. Patients were assigned to tourniquet or BP cuff for target vein dilation randomly. Nurses prepared the patient for PIV attempt by either placing a BP cuff inflated to 150 mm Hg or placing a tourniquet on the chosen extremity. The extremity was draped to blind the physician to assignment. Physicians then attempted ultrasound-guided PIV. Failures were defined as IVs requiring greater than 3 ultrasound-guided attempts or 30 minutes, or patient intolerance. If failure occurred, the physician was unblinded; and the patient could be crossed over and reattempted. Thirty-eight patients were enrolled. The success rate for the tourniquet group (n = 17) and BP cuff group (n = 21) was 82.4% and 47.6%, respectively (P = .04). There were no differences between groups for vessel depth, diameter, or procedure time. Six in the BP cuff group were crossed over and had successful PIV obtained with tourniquet. Tourniquet is superior to BP cuff for target vein dilation in ultrasound-guided PIV. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Cerebral blood flow simulations in realistic geometries

    Directory of Open Access Journals (Sweden)

    Szopos Marcela

    2012-04-01

    Full Text Available The aim of this work is to perform the computation of the blood flow in all the cerebral network, obtained from medical images as angiographies. We use free finite elements codes as FreeFEM++. We first test the code on analytical solutions in simplified geometries. Then, we study the influence of boundary conditions on the flow and we finally perform first computations on realistic meshes. L’objectif est ici de simuler l’écoulement sanguin dans tout le réseau cérébral (artériel et veineux obtenu à partir d’angiographies cérébrales 3D à l’aide de logiciels d’éléments finis libres, comme FreeFEM++. Nous menons d’abord une étude détaillée des résultats sur des solutions analytiques et l’influence des conditions limites à imposer dans des géométries simplifiées avant de travailler sur les maillages réalistes.

  5. Renal blood flow in sepsis: a complex issue

    OpenAIRE

    Molitoris, Bruce A

    2005-01-01

    The clinical complexity of sepsis and the regional variability in renal blood flow present a difficult challenge for the clinician or investigator in understanding the role and clinical importance of reduced blood flow in the pathophysiology of sepsis-induced acute renal failure. Understanding the role of regional microvasculature flow and interactions between endothelium and white blood cells in the local delivery of oxygen and substrates is of critical importance. Therefore, measuring total...

  6. Regional cerebral blood flow in the patient with brain tumor

    International Nuclear Information System (INIS)

    Tsuchida, Shohei

    1993-01-01

    Regional cerebral blood flow (rCBF) was measured with xenon-enhanced CT (Xe-CT) in 21 cases of intracranial tumors (13 meningiomas, 5 gliomas, 3 metastatic brain tumors). Peritumoral edema was graded as mild, moderate or severe based on the extent of edema on CT and MRI. According to intratumoral blood flow distribution patterns, three patterns were classified as central type with relatively high blood flow at the center of the tumor, homogeneous type with an almost homogeneous blood flow distribution, and marginal type with relatively high blood flow at the periphery of the tumor. High grade astrocytoma and metastatic brain tumor showed marginal type blood flow and moderate or severe edema except in one case. Five meningiomas with severe peritumoral edema revealed marginal type blood flow and four with mild peritumoral edema showed central type blood flow, except for one case. No correlation was found between the extent of peritumoral edema and histological subtype, tumor size, location, duration of clinical history, vascularization on angiogram, and mean blood flow in the tumor. These results suggest that blood flow distribution patterns within the tumor may affect the extension of peritumoral edema. Pre- and postoperative rCBFs were evaluated with Xe-CT and IMP-SPECT in 7 cases, mean rCBF of peritumoral edema was 6.2 ml/100 g/min preoperatively, and discrepancy between rCBF on Xe-CT and that on IMP-SPECT was shown in the remote cortical region ipsilateral to the tumor. Postoperative rCBF revealed an improved blood flow in both adjacent and remote areas, suggesting that the decreased blood flow associated with brain tumors might be relieved after surgery. (author) 53 refs

  7. Assessment of hand blood flow: a modified technique

    International Nuclear Information System (INIS)

    Kirsh, J.C.; Tepperman, P.S.

    1985-01-01

    A blood flow artifact has been identified with the conventional bolus-injection technique in radionuclide studies of hand disorders. The artifact, consisting of increased blood flow on the injected side, was demonstrated in 22 of 25 subjects. Using a modified injection technique to allow time for local blood flow to return to the basal state, the artifact could be eliminated in 19 of 23 additional subjects. Use of this simple protocol should help avoid misinterpretation of blood flow asymmetry in the assessment of hand disorders

  8. Effect of fluocinolone acetonide cream on human skin blood flow

    International Nuclear Information System (INIS)

    Chimoskey, J.E.; Holloway, A. Jr.; Flanagan, W.J.

    1975-01-01

    Blood flow rate was measured in the forearm skin of human subjects exposed to ultraviolet irradiation. Blood flow was determined by the 133 Xe disappearance technique 18 hr after ultraviolet (UV) irradiation with a Westinghouse RS sunlamp held 10 inches from the skin for 10 min. Ultraviolet irradiation caused skin blood flow to increase. Application of fluocinolone acetonide cream, 0.025 percent, 4 times in the 16 hr following UV irradiation had no effect on either control skin blood flow or the UV-induced hyperemia

  9. Bone blood flow after spinal paralysis in the rat

    International Nuclear Information System (INIS)

    Takahashi, H.; Yamamuro, T.; Okumura, H.; Kasai, R.; Tada, K.

    1990-01-01

    The goal of this study was to investigate the acute and chronic effects of paralysis induced by spinal cord section or sciatic neurotomy on bone blood flow in the rat. Regional bone blood flow was measured in the early stage with the hydrogen washout technique and the change of whole bone blood flow was measured in the early and the late stages with the radioactive microsphere technique. Four to 6 h after cordotomy at the level of the 13th thoracic vertebra, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.01). After hemicordotomy with rhizotomy at the same level, the regional bone blood flow in the denervated tibia increased significantly (p less than 0.05) 6 h postoperatively. The whole bone blood flow in the denervated tibia had also increased significantly (p less than 0.05) at 6 h and at 4 and 12 weeks postoperatively. After sciatic neurotomy, the regional and the whole bone blood flow in the paralytic tibia did not change significantly. The present study demonstrated that monoplegic paralysis caused an increase in bone blood flow in the denervated hind limb from a very early stage. It was suggested that the spinal nervous system contributed to the control of bone blood flow

  10. Effect of Metoclopramide on Portal Blood Flow in Patients with Liver Cirrhosis: Evaluation by the Pulsed Doppler System

    International Nuclear Information System (INIS)

    Baik, Soon Koo; Lee, Yong Gyu; Hong, Sa Joon; Lee, Seong Wu; Lee, Dong Ki; Kwong, Sang Ok

    1994-01-01

    Metoclopramide is known to lower the intravariceal flow by raising the lower esophageal sphincter pressure and consequently decreases the portal blood flow. So we designed this study to assess the effect of metoclopramide on portal blood flow in cirrhotic patients using pulsed Doppler system. By using pulsed Doppler ultrasound, portal blood velocity, diameter of the portal vein, portal blood flow, blood pressure and pulse rate were measured at 15, 30 and 60 minutes after administration of 20mg metoclopramide in 16cirrhotic patients and compared with the basal values. In order 10 cirrhotic patients, normal saline was administrated, and the above mentioned parameters were measured. Wothin 15 minutes after intravenous administration of 20mg metoclopramide, portal blood velocity and portal blood flow decreased significantly, from 12.45+2.64 to 11.80+2.55cm/sec and from 1006.3+407.1 to 974.4+414.7ml/min, respectively(P<0.05). In placebo group,there was no significant change in measured parameters after administration of normal saline. These results support the hypothesis that metoclopramide significantly decreases the portal blood flow transiently in cirrhotic patients with portal hypertension

  11. Renal and femoral venous blood flows are regulated by different mechanisms dependent on α-adrenergic receptor subtypes and nitric oxide in anesthetized rats.

    Science.gov (United States)

    Fioretti, Alexandre C; Ogihara, Cristiana A; Cafarchio, Eduardo M; Venancio, Daniel P; de Almeida, Roberto Lopes; Antonio, Bruno B; Sato, Monica A

    2017-12-01

    Venous and arterial walls are responsive to sympathetic system and circulating substances, nevertheless, very few is known about the venous blood flow regulation simultaneously to arterial vascular beds. In this study, we compared the venous and arterial blood flow regulation in visceral and muscular beds upon injection of different doses of vasoactive drugs which act in arterial vascular beds. Anesthetized adult male Wistar rats underwent to right femoral artery and vein cannulation for hemodynamic recordings and infusion of drugs. Doppler flow probes were placed around the left renal artery and vein, and left femoral artery and vein to evaluate the changes in flood flow. Phenylephrine (PHE) injection (α 1 -adrenergic receptor agonist) elicited vasoconstriction in all arteries and veins. Intravenous prazosin (PZS) (1mg/kg, α 1 -adrenergic receptor blocker) caused renal artery vasodilation, but not in the other beds. Vasoconstrictor effect of PHE was abolished by PZS in all vascular beds, except in femoral vein. Phentolamine (PTL) injection (1mg/kg, α 1 /α 2 -adrenergic receptor blocker) produced renal artery vasodilation with no change in other beds. After PTL, the vasoconstriction evoked by PHE was abolished in all vascular beds. Sodium Nitroprusside (SNP), a nitric oxide donor, elicited vasodilation in all beds, and after PTL but not post PZS injection, SNP enhanced the vasodilatory effect in femoral vein. Our findings suggest that the vasoconstriction in renal and femoral veins is mediated by different subtypes of α-adrenoceptors. The nitric oxide-dependent vasodilation in femoral vein enhances when α 2 -adrenoceptors are not under stimulation, but not in the other vascular beds investigated. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Characterization of a porcine model of chronic superficial varicose veins.

    Science.gov (United States)

    Jones, Gregory T; Grant, Mark W; Thomson, Ian A; Hill, B Geraldine; van Rij, André M

    2009-06-01

    Previous animal models of venous disease, while inducing venous hypertension and valvular insufficiency, do not produce superficial varicose veins. In this study, we aimed to develop and characterize a pig-based model of superficial varicose veins. Right femoral arteriovenous fistulae (AVF) were surgically fashioned in young adult pigs. Animals were examined at postoperative times up to 15 weeks to determine the development of varicose veins and measurement of both blood pressure and flow velocities within the superficial thigh veins. Histology and vascular corrosion casts were used to characterize the resulting structural venous alterations. Porcine pathophysiological features were compared with those of human primary superficial varicose veins. Gross superficial varicosities developed over the ipsilateral medial thigh region after an initial lag period of 1-2 weeks. Veins demonstrated retrograde filling with valvular incompetence, and a moderate, non-pulsatile, venous hypertension, which was altered by changes in posture and Valsalva. Venous blood flow velocities were elevated to 15-30 cm/s in varicose veins. Structurally, pig varicose veins were enlarged, tortuous, had valvular degeneration, and regions of focal medial atrophy with or without overlying intimal thickening. The superficial varicose veins, which developed within this model, have a pathophysiology that is consistent with that observed in humans. The porcine femoral AVF model is proposed as a suitable experimental model to evaluate the pathobiology of superficial venous disease. It may also be suitable for the evaluation of treatment interventions including drug therapy.

  13. Comparison of utility of blood cultures from intravascular catheters and peripheral veins: a systematic review and decision analysis.

    Science.gov (United States)

    Falagas, Matthew E; Kazantzi, Maria S; Bliziotis, Ioannis A

    2008-01-01

    Blood cultures are sometimes obtained from intravascular catheters for convenience. However, there is controversy regarding this practice. The authors compared the diagnostic test characteristics of blood cultures obtained from intravascular catheters and peripheral veins. Relevant studies for inclusion in this review were identified through PubMed (January 1970-October 2005) and the Cochrane Central Register of Controlled Trials. Studies that reported clear definitions of true bacteraemia were included in the analysis. Two reviewers independently extracted the data. Six studies were included in the analysis, providing data for 2677 pairs of blood cultures obtained from an intravascular catheter and a peripheral venipuncture. A culture obtained from an intravascular catheter was found to be a diagnostic test for bacteraemia with better sensitivity (OR 1.85, 95 % CI 1.14-2.99, fixed effects model) and better negative predictive value (almost with statistical significance) (OR 1.55, 95 % CI 0.999-2.39, fixed effects model) but with less specificity (OR 0.33, 95 % CI 0.18-0.59, random effects model) and lower positive predictive value (OR 0.41, 95 % CI 0.23-0.76, random effects model) compared to a culture taken by peripheral venipuncture. In a group of 1000 patients, eight additional patients with true bacteraemia would be identified and 59 falsely diagnosed as having bacteraemia by a blood culture obtained from an intravascular catheter compared to results of the peripheral blood culture. Given the consequences of undertreating patients with bacteraemia, the authors believe that, based on the available evidence, at least one blood culture should be obtained from the intravascular catheter.

  14. Vasopressin and nitroglycerin decrease portal and hepatic venous pressure and hepato-splanchnic blood flow.

    Science.gov (United States)

    Wisén, E; Svennerholm, K; Bown, L S; Houltz, E; Rizell, M; Lundin, S; Ricksten, S-E

    2018-03-26

    Various methods are used to reduce venous blood pressure in the hepato-splanchnic circulation, and hence minimise blood loss during liver surgery. Previous studies show that combination of vasopressin and nitroglycerin reduces portal pressure and flow in patients with portal hypertension, and in this study we investigated this combination in patients with normal portal pressure. In all, 13 patients were studied. Measurements were made twice to confirm baseline (C1 and BL), during vasopressin infusion 4.8 U/h (V), and during vasopressin infusion combined with nitroglycerin infusion (V + N). Portal venous pressure (PVP), hepatic venous pressure (HVP), central haemodynamics and arterial and venous blood gases were obtained at each measuring point, and portal (splanchnic) and hepato-splanchnic blood flow changes were calculated. Vasopressin alone did not affect PVP, whereas HVP increased slightly. In combination with nitroglycerin, PVP decreased from 10.1 ± 1.6 to 8.9 ± 1.3 mmHg (P HVP decreased from 7.9 ± 1.9 to 6.2 ± 1.3 mmHg (P = 0.001). Vasopressin reduced portal blood flow by 47 ± 19% and hepatic venous flow by 11 ± 18%, respectively. Addition of nitroglycerin further reduced portal- and hepatic flow by 55 ± 13% and 30 ± 13%, respectively. Vasopressin alone had minor effects on central haemodynamics, whereas addition of nitroglycerin reduced cardiac index (3.2 ± 0.7 to 2.7 ± 0.5; P < 0.0001). The arterial-portal vein lactate gradient was unaffected. The combination of vasopressin and nitroglycerin decreases portal pressure and hepato-splanchnic blood flow, and could be a potential treatment to reduce bleeding in liver resection surgery. © 2018 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  15. Data adaptive estimation of transversal blood flow velocities

    DEFF Research Database (Denmark)

    Pirnia, E.; Jakobsson, A.; Gudmundson, E.

    2014-01-01

    the transversal blood flow. In this paper, we propose a novel data-adaptive blood flow estimator exploiting this modulation scheme. Using realistic Field II simulations, the proposed estimator is shown to achieve a notable performance improvement as compared to current state-of-the-art techniques.......The examination of blood flow inside the body may yield important information about vascular anomalies, such as possible indications of, for example, stenosis. Current Medical ultrasound systems suffer from only allowing for measuring the blood flow velocity along the direction of irradiation......, posing natural difficulties due to the complex behaviour of blood flow, and due to the natural orientation of most blood vessels. Recently, a transversal modulation scheme was introduced to induce also an oscillation along the transversal direction, thereby allowing for the measurement of also...

  16. Daily rhythm of cerebral blood flow velocity

    Directory of Open Access Journals (Sweden)

    Spielman Arthur J

    2005-03-01

    Full Text Available Abstract Background CBFV (cerebral blood flow velocity is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1 CBFV changes are due to sleep-associated processes or 2 time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of sustained wakefulness to determine whether CBFV exhibits fluctuations associated with time of day. Methods Eleven subjects underwent a modified constant routine protocol. CBFV from the middle cerebral artery was monitored by chronic recording of Transcranial Doppler (TCD ultrasonography. Other variables included core body temperature (CBT, end-tidal carbon dioxide (EtCO2, blood pressure, and heart rate. Salivary dim light melatonin onset (DLMO served as a measure of endogenous circadian phase position. Results A non-linear multiple regression, cosine fit analysis revealed that both the CBT and CBFV rhythm fit a 24 hour rhythm (R2 = 0.62 and R2 = 0.68, respectively. Circadian phase position of CBT occurred at 6:05 am while CBFV occurred at 12:02 pm, revealing a six hour, or 90 degree difference between these two rhythms (t = 4.9, df = 10, p Conclusion In conclusion, time of day variations in CBFV have an approximately 24 hour rhythm under constant conditions, suggesting regulation by a circadian oscillator. The 90 degree-phase angle difference between the CBT and CBFV rhythms may help explain previous findings of lower CBFV values in the morning. The phase difference occurs at a time period during which cognitive performance decrements have been observed and when both cardiovascular and cerebrovascular events occur more frequently. The mechanisms underlying this phase angle difference require further exploration.

  17. Finger vein extraction using gradient normalization and principal curvature

    Science.gov (United States)

    Choi, Joon Hwan; Song, Wonseok; Kim, Taejeong; Lee, Seung-Rae; Kim, Hee Chan

    2009-02-01

    Finger vein authentication is a personal identification technology using finger vein images acquired by infrared imaging. It is one of the newest technologies in biometrics. Its main advantage over other biometrics is the low risk of forgery or theft, due to the fact that finger veins are not normally visible to others. Extracting finger vein patterns from infrared images is the most difficult part in finger vein authentication. Uneven illumination, varying tissues and bones, and changes in the physical conditions and the blood flow make the thickness and brightness of the same vein different in each acquisition. Accordingly, extracting finger veins at their accurate positions regardless of their thickness and brightness is necessary for accurate personal identification. For this purpose, we propose a new finger vein extraction method which is composed of gradient normalization, principal curvature calculation, and binarization. As local brightness variation has little effect on the curvature and as gradient normalization makes the curvature fairly uniform at vein pixels, our method effectively extracts finger vein patterns regardless of the vein thickness or brightness. In our experiment, the proposed method showed notable improvement as compared with the existing methods.

  18. Cerebellar blood flow in methylmercury poisoning (Minamata disease)

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, K.; Korogi, Y.; Tomiguchi, S.; Takahashi, M. [Dept. of Radiology, Kumamoto University School of Medicine (Japan); Okajima, T. [Dept. of Neurology, Johnan Hospital, Maihara, Johnan-mochi (Japan); Sato, H. [Dept. of Neurology, Minamata City General Hospital and Medical Centre (Japan)

    2001-04-01

    We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99 m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part. (orig.)

  19. Cerebellar blood flow in methylmercury poisoning (Minamata disease)

    International Nuclear Information System (INIS)

    Itoh, K.; Korogi, Y.; Tomiguchi, S.; Takahashi, M.; Okajima, T.; Sato, H.

    2001-01-01

    We looked at regional cerebellar blood flow in patients with Minamata disease (MD) using technetium-99 m ethyl cysteinate dimer (99m-Tc-ECD). We carried out single-photon emission computed tomography (SPECT) on 15 patients with MD (eight men, seven women, aged 51-78 years, mean 70.5 years) and 11 control subjects (eight men, three women, aged 62-80 years, mean 72.5 years). Regional blood flow was measured in the superior, middle, and inferior portions of the cerebellar hemispheres, and the frontal, temporal and occipital cerebral lobes. The degree of cerebellar atrophy was assessed on MRI. There were significant differences in regional blood flow in all parts of the cerebellum between patients and control, but no significant decrease was observed in the cerebrum. Blood flow was lower in the inferior cerebellum than in the other parts. Even in patients without cerebellar atrophy, flow was significantly decreased regional blood flow in the inferior part. (orig.)

  20. Reflux venous flow in dural sinus and internal jugular vein on 3D time-of-flight MR angiography

    International Nuclear Information System (INIS)

    Jang, Jinhee; Kim, Bum-soo; Kim, Bom-yi; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin; Byun, Jae Young

    2013-01-01

    Reflux venous signal on the brain and neck time-of-flight magnetic resonance angiography (TOF MRA) is thought to be related to a compressed left brachiocephalic vein. This study is aimed to assess the prevalence of venous reflux flow in internal jugular vein (IJV), sigmoid sinus/transverse sinus (SS/TS), and inferior petrosal sinus (IPS) on the brain and neck TOF MRA and its pattern. From the radiology database, 3,475 patients (1,526 men, 1,949 women, age range 19-94, median age 62 years) with brain and neck standard 3D TOF MRA at 3 T and 1.5 T were identified. Rotational maximal intensity projection images of 3D TOF MRA were assessed for the presence of reflux flow in IJV, IPS, and SS/TS. Fifty-five patients (1.6 %) had reflux flow, all in the left side. It was more prevalent in females (n = 43/1,949, 2.2 %) than in males (n = 12/1,526, 0.8 %) (p = 0.001). The mean age of patients with reflux flow (66 years old) was older than those (60 years old) without reflux flow (p = 0.001). Three patients had arteriovenous shunt in the left arm for hemodialysis. Of the remaining 52 patients, reflux was seen on IJV in 35 patients (67.3 %). There were more patients with reflux flow seen on SS/TS (n = 34) than on IPS (n = 25). Venous reflux flow on TOF MRA is infrequently observed, and reflux pattern is variable. Because it is exclusively located in the left side, the reflux signal on TOF MRA could be an alarm for an undesirable candidate for a contrast injection on the left side for contrast-enhanced imaging study. (orig.)

  1. When to use femoral vein injection for diagnosis of patent foramen ovale-Effect of a persistent eustachian valve on right atrial flow patterns during contrast transesophageal echocardiography.

    Science.gov (United States)

    Koh, Tat W

    2017-05-01

    Contrast echocardiography using agitated saline injected into the antecubital vein is the most common method used for the diagnosis of patent foramen ovale. We describe a case whereby the presence of a persistent eustachian valve and a "negative contrast sign" during contrast transesophageal echocardiography raised suspicion of a false-negative result. Femoral vein injection of contrast successfully demonstrated a patent foramen ovale. Femoral vein injection should be considered if this scenario is recognized because the eustachian valve directs blood preferentially from the inferior vena cava toward the interatrial septum and this route may prove to be more reliable. © 2017, Wiley Periodicals, Inc.

  2. Left coronary arterial blood flow: Noninvasive detection by Doppler US

    International Nuclear Information System (INIS)

    Gramiak, R.; Holen, J.; Moss, A.J.; Gutierrez, O.H.; Picone, A.L.; Roe, S.A.

    1986-01-01

    Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs

  3. Regional cerebral blood flow in neuropediatrics

    International Nuclear Information System (INIS)

    Junik, R.

    2001-01-01

    Single photon emission computed tomography can effectively and non-invasively measure regional blood flow. Mostly used 99mTc-HMPAO is a safe brain imaging agent for pediatric applications. The radiation dose is acceptable. Knowledge of the normal rCBF pattern, including normal asymmetries and variations due to age, is necessary prerequisite for the evaluation and reporting of the results of 99mTc-HMPAO brain SPECT studies in clinical practice. The interpretation of he rCBF study in a child requires knowledge of normal brain maturation. The aim of the present review is to focus on the contribution to clinical developmental neurology of SPECT The clinical use of SPECT in developmental neurology are epilepsy, brain death, acute neurological loss including stroke, language disorders, cerebral palsy, high-risk neonates, hypertension due to renovascular disease, traumatic brain injury, migraine, anorexia nervosa, autism, Gilles de la Tourette syndrome, attention deficit disorder-hyperactivity, and monitoring therapy. Sedation is not routinely used, rather each child is evaluated. However, drug sedation is mandatory in some uncooperative children. (author)

  4. Role of four-dimensional echocardiography with high-definition flow imaging and spatiotemporal image correlation in detecting fetal pulmonary veins.

    Science.gov (United States)

    Sun, Xue; Zhang, Ying; Fan, Miao; Wang, Yu; Wang, Meilian; Siddiqui, Faiza Amber; Sun, Wei; Sun, Feifei; Zhang, Dongyu; Lei, Wenjia; Hu, Guyue

    2017-06-01

    Prenatal diagnosis of fetal total anomalous pulmonary vein connection (TAPVC) remains challenging for most screening sonographers. The purpose of this study was to evaluate the use of four-dimensional echocardiography with high-definition flow imaging and spatiotemporal image correlation (4D-HDFI) in identifying pulmonary veins in normal and TAPVC fetuses. We retrospectively reviewed and performed 4D-HDFI in 204 normal and 12 fetuses with confirmed diagnosis of TAPVC. Cardiac volumes were available for postanalysis to obtain 4D-rendered images of the pulmonary veins. For the normal fetuses, two other traditional modalities including color Doppler and HDFI were used to detect the number of pulmonary veins and comparisons were made between each of these traditional methods and 4D-HDFI. For conventional echocardiography, HDFI modality was superior to color Doppler in detecting more pulmonary veins in normal fetuses throughout the gestational period. 4D-HDFI was the best method during the second trimester of pregnancy in identifying normal fetal pulmonary veins. 4D-HDFI images vividly depicted the figure, course, and drainage of pulmonary veins in both normal and TAPVC fetuses. HDFI and the advanced 4D-HDFI technique could facilitate identification of the anatomical features of pulmonary veins in both normal and TAPVC fetuses; 4D-HDFI therefore provides additional and more precise information than conventional echocardiography techniques. © 2017, Wiley Periodicals, Inc.

  5. Blood flow velocity in migraine attacks - a transcranial Doppler study

    International Nuclear Information System (INIS)

    Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D.

    1991-01-01

    A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs

  6. Subcutaneous blood flow during insulin-induced hypoglycaemia

    DEFF Research Database (Denmark)

    Hilsted, J; Madsbad, S; Sestoft, L

    1982-01-01

    Subcutaneous blood flow was measured preceding insulin-induced hypoglycaemia, at the onset of hypoglycaemic symptoms and 2 h later in juvenile diabetics with and without autonomic neuropathy and in normal males. In all groups subcutaneous blood flow decreased at the onset of hypoglycaemic symptom...

  7. Measurement of absolute bone blood flow by positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Nahmias, C.; Cockshott, W.P.; Garnett, E.S.; Belbeck, L.W.

    1986-03-01

    A method of measuring bone blood flow has been developed using /sup 18/F sodium fluoride and positron emission tomography. The blood flow levels are in line with those obtained experimentally from microsphere embolisation. This investigative method could be applied to elucidate a number of clinical questions involving bone perfusion.

  8. Modeling skin blood flow: a neuro-physiological approach

    NARCIS (Netherlands)

    Kingma, B.R.M.; Saris, W.H.M.; Frijns, A.J.H.; Steenhoven, van A.A.; Marken Lichtenbelt, van W.D.

    2010-01-01

    In humans skin blood flow (SBF) plays a major role in body heat loss. Therefore the accuracy of models ofhuman thermoregulation depends for a great deal on their ability to predict skin blood flow. Most SBFmodelsuse body temperatures directly for calculation of skin perfusion. However, humans do not

  9. Blood flow velocity in migraine attacks - a transcranial Doppler study

    Energy Technology Data Exchange (ETDEWEB)

    Zwetsloot, C.P.; Caekebeke, J.F.V.; Jansen, J.C.; Odink, J.; Ferrari, M.D. (Rijksuniversiteit Leiden (Netherlands))

    1991-05-01

    A pulsed Doppler device was used to measure blood flow velocities in the common carotid artery, the extracranial part of the internal carotid artery, the external carotid artery, the middle cerebral artery, and the anterior cerebral artery in 31 migraneurs without aura (n=27) and with aura (n=4), both during and ouside an attack. The aims were to compare blood flow velocity during and between migraine attacks and to study asymmetries of the blood flow velocity. Compared with blood flow velocity values obtained in the attack-free interval, blood flow velocity was lower during attacks without aura in both common carotid arteries, but not in the other extra- and intracranial vessels which were examined. However, during attacks of migraine with aura, blood flow velocity tended to be lower in all examined vessels. There were no asymmetries of the blood flow velocity. It is suggested that during migraine attacks without aura there is a dissociation in blood flow regulation in the common carotid and middle cerebral arteries. 20 refs., 2 tabs.

  10. Self-separation of blood plasma from whole blood during the capillary flow in microchannel

    Science.gov (United States)

    Nunna, Bharath Babu; Zhuang, Shiqiang; Lee, Eon Soo

    2017-11-01

    Self-separation of blood plasma from whole blood in microchannels is of great importance due to the enormous range of applications in healthcare and diagnostics. Blood is a multiphase complex fluid, composed of cells suspended in blood plasma. RBCs are the suspended particles whose shape changes during the flow of blood. The primary constituents of blood are erythrocytes or red blood cells (RBCs), leukocytes or white blood cells (WBCs), thrombocytes or platelets and blood plasma. The existence of RBCs in blood makes the blood a non-Newtonian fluid. The current study of separation of blood plasma from whole blood during self-driven flows in a single microchannel without bifurcation, by enhancing the capillary effects. The change in the capillary effect results in a change in contact angle which directly influences the capillary flow. The flow velocity directly influences the net force acting on the RBCs and influence the separation process. The experiments are performed on the PDMS microchannels with different contact angles by altering the surface characteristics using plasma treatment. The change in the separation length is studied during the capillary flow of blood in microchannel. Bharath Babu Nunna is a researcher in mechanical engineering and implementing the novel and innovative technologies in the biomedical devices to enhance the sensitivity of the disease diagnosis.

  11. Our experience of blood flow measurements using radioactive tracers

    International Nuclear Information System (INIS)

    Danet, Bernard.

    1974-01-01

    A critical study of blood flow measuring methods is proposed. After a review of the various diffusible and non-diffusible radioactive tracers and the corresponding detector systems, the principles which allow to measure blood flow from the data so obtained, are studied. There is a different principle of flow measurement for each type of tracer. The theory of flow measurement using non-diffusible tracers (human serum albumin labelled with 131 I or sup(99m)Tc, 113 In-labelled siderophiline) and its application to cardiac flow measurement are described first. Then the theory of flow measurement using diffusible tracers ( 133 Xe, 85 Kr) and its application to measurement of blood flow through tissues (muscles and kidney particularly) are described. A personal experience of this various flow measurements is reported. The results obtained, the difficulties encountered and the improvments proposed are developed [fr

  12. Myocardial blood flow during induced aortic hypertension in dogs

    International Nuclear Information System (INIS)

    Thai, B.N.; Levesque, M.J.; Nerem, R.M.

    1986-01-01

    Myocardial blood flow was measured in anesthetized dogs during control conditions and under conditions where the aortic pressure was increased due to aortic constriction or during infusion. Blood flow was measured using the radioactive microsphere technique. Radioactive microspheres (15 m Ce-141, Sr-85, and Sc-46) were injected under control, aortic constriction and arterenol infusion in four dogs and under control conditions in two others. All microsphere injections were performed under stabilized conditions. It was found that coronary blood flow rose by 80% during aortic constriction and by 158% during arterenol infusion (P < 0.05). This increase in blood flow was not uniform throughout the heart, and higher increases were observed in the middle and apex regions of the left ventricle. Furthermore, under hypertension the increase in blood flow in LAD (left anterior descending) perfused territories was slightly higher than that in CFX (left circumflex) perfused territories

  13. Mammary blood flow regulation in the nursing rabbit

    International Nuclear Information System (INIS)

    Katz, M.; Creasy, R.K.

    1984-01-01

    Cardiac output and mammary blood flow distribution prior to and after suckling were studied in 10 nursing rabbits by means of radionuclide-labeled microspheres. Suckling was followed by a 5.8% rise in cardiac output and a 20.4% rise in mammary blood flow. Determinations of intraglandular blood flow distribution have shown that there was a 43% increase in blood flow to the glands suckled from as compared to a 22.7% rise to the contralateral untouched glands and a 4.9% rise in the remainder of untouched glands. The conclusion is that a local mechanism may be involved in the regulation of mammary blood flow in the nursing rabbit

  14. Thermographic venous blood flow characterization with external cooling stimulation

    Science.gov (United States)

    Saxena, Ashish; Ng, E. Y. K.; Raman, Vignesh

    2018-05-01

    Experimental characterization of blood flow in a human forearm is done with the application of continuous external cooling based active thermography method. Qualitative and quantitative detection of the blood vessel in a thermal image is done, along with the evaluation of blood vessel diameter, blood flow direction, and velocity in the target blood vessel. Subtraction based image manipulation is performed to enhance the feature contrast of the thermal image acquired after the removal of external cooling. To demonstrate the effect of occlusion diseases (obstruction), an external cuff based occlusion is applied after the removal of cooling and its effect on the skin rewarming is studied. Using external cooling, a transit time method based blood flow velocity estimation is done. From the results obtained, it is evident that an external cooling based active thermography method can be used to develop a diagnosis tool for superficial blood vessel diseases.

  15. Quantitative myocardial blood flow with Rubidium-82 PET

    DEFF Research Database (Denmark)

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identificat......Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1...... global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability...

  16. Influence of immune-mediated hemolytic anemia on flow velocities in the portal vein and caudal vena cava measured by use of pulsed-wave Doppler ultrasonography in dogs.

    Science.gov (United States)

    Smith, Rachel Policelli; Koenigshof, Amy M; Smith, Daniel J; Strom, Phillip R; Nelson, Nathan C

    2018-05-01

    OBJECTIVE To compare blood flow velocities of the portal vein (PV) and caudal vena cava (CVC) measured by use of pulsed-wave Doppler ultrasonography in clinically normal dogs and dogs with primary immune-mediated hemolytic anemia (IMHA). ANIMALS 11 client-owned dogs admitted to a veterinary teaching hospital for management of primary IMHA and 21 staff- or student-owned clinically normal dogs. PROCEDURES Flow velocities in the PV and CVC at the porta hepatis were evaluated in conscious unsedated dogs with concurrent ECG monitoring; evaluations were performed before dogs with IMHA received heparin or blood transfusions. Three measurements of peak velocity at end expiration were obtained for each vessel, and the mean was calculated. Results were compared between IMHA and control groups. RESULTS Mean ± SD blood flow velocity in the CVC differed between control (63.0 ± 18.6 cm/s) and IMHA (104 ± 36.9 cm/s) groups. Variance in dogs with IMHA was significantly greater than that for the clinically normal dogs. No significant difference in blood flow velocity in the PV was detected between IMHA and control dogs. CONCLUSIONS AND CLINICAL RELEVANCE Higher blood flow velocities were detected by use of pulsed-wave Doppler ultrasonography in the CVC of dogs with naturally occurring IMHA and may be used to predict anemia in patients suspected of having IMHA.

  17. Effect of atrial systole on canine and porcine coronary blood flow.

    Science.gov (United States)

    Bellamy, R F

    1981-09-01

    A feature of phasic coronary flow patterns recorded in conscious chronically instrumented dogs is the atrial cove--a transient depression of arterial flow that occurs during atrial systole. The association between the hemodynamic effects of atrial systole and the atrial cove was studied in anesthetized dogs and pigs with complete heart block. Many atrial coves are available for study in these preparations because atrial activity continues unabated during the diastolic ventricular arrest that follows cessation of electrical pacing. The effect of atrial systole is to translate the pressure-flow relation found during diastole to a higher intercept pressure without change in slope. The increase in the intercept pressure equals the increase in intramyocardial pressure measured with microtransducers embedded in the left ventricular wall. The decrement in flow during the atrial cove is a direct function of the change in intramyocardial pressure and an inverse function of coronary vascular resistance. Each atrial systole is associated with a forward flow transient in the coronary veins, the peak of which occurs at the same instant as does the nadir of atrial flow. These data suggest that the coronary vessels are acting as collapsible tubes and that the waterfall model of the coronary circulation is applicable. The following sequence is proposed to account for the atrial cove. Atrial systole ejects a bolus of blood into the left ventricle increasing both ventricular cavity and intramyocardial pressures. The increase in intramyocardial pressure raises the back pressure opposing coronary flow, reducing the arterial perfusion pressure gradient and causing flow to fall.

  18. Blood flow behavior in microchannels: past, current and future trends

    OpenAIRE

    Lima, R.; Ishikawa, Takuji; Imai, Yohsuke; Yamaguchi, Takami

    2012-01-01

    Over the years, various experimental methods have been applied in an effort to understand the blood flow behavior in microcirculation. Most of our current knowledge in microcirculation is based on macroscopic flow phenomena such as Fahraeus effect and Fahraeus-Linqvist effect. The development of optical experimental techniques has contributed to obtain possible explanations on the way the blood flows through microvessels. Although the past results have been encouraging, detailed s...

  19. Noninvasive measurement of an index of renal blood flow

    International Nuclear Information System (INIS)

    Powers, T.A.; Rees, R.S.; Bowen, R.D.

    1983-01-01

    A new technique for the noninvasive measurement of an index of renal blood flow is described. The method utilizes ultrasound determined renal volume and radionuclide assessment of the mean transit time of a pertechnetate bolus through the kidneys. From this information a value for flow is calculated according to compartmental analysis principles. There is good correlation between renal blood flow estimated by this technique and that determined by microsphere injection

  20. Rat muscle blood flows during high-speed locomotion

    International Nuclear Information System (INIS)

    Armstrong, R.B.; Laughlin, M.H.

    1985-01-01

    We previously studied blood flow distribution within and among rat muscles as a function of speed from walking (15 m/min) through galloping (75 m/min) on a motor-driven treadmill. The results showed that muscle blood flows continued to increase as a function of speed through 75 m/min. The purpose of the present study was to have rats run up to maximal treadmill speeds to determine if blood flows in the muscles reach a plateau as a function of running speed over the animals normal range of locomotory speeds. Muscle blood flows were measured with radiolabeled microspheres at 1 min of running at 75, 90, and 105 m/min in male Sprague-Dawley rats. The data indicate that even at these relatively high treadmill speeds there was still no clear evidence of a plateau in blood flow in most of the hindlimb muscles. Flows in most muscles continued to increase as a function of speed. These observed patterns of blood flow vs. running speed may have resulted from the rigorous selection of rats that were capable of performing the high-intensity exercise and thus only be representative of a highly specific population of animals. On the other hand, the data could be interpreted to indicate that the cardiovascular potential during exercise is considerably higher in laboratory rats than has normally been assumed and that inadequate blood flow delivery to the muscles does not serve as a major limitation to their locomotory performance

  1. Effects of Red Blood Cell Aggregation on the Apparent Viscosity of Blood Flow in Tubes.

    Science.gov (United States)

    Hitt, Darren L.; Lowe, Mary L.

    1996-11-01

    In arterioles and venules (20-200μ diameter), the low shear rates enable red blood cells to form aggregate structures of varying sizes and morphology. The size and distribution of the aggregates affect the flow impedance within a microvascular network; this effect may be characterized by an "apparent viscosity". In this study, we measure the apparent viscosity of blood flow in 50μ glass tubes as a function of shear rate and red blood cell volume fraction (hematocrit); for a fixed tube geometry and an imposed flow rate, the viscosity is determined by measuring the pressure drop across the tube. To correlate the apparent viscosity with the size and spatial distribution of the aggregates in the flow, video images of the flow are recorded and analyzed using power spectral techniques. Pig blood and sheep blood are used as the models for aggregating and non-aggregating blood, respectively. Supported by NSF PFF Award CTS-9253633

  2. Spiral blood flow in aorta-renal bifurcation models.

    Science.gov (United States)

    Javadzadegan, Ashkan; Simmons, Anne; Barber, Tracie

    2016-01-01

    The presence of a spiral arterial blood flow pattern in humans has been widely accepted. It is believed that this spiral component of the blood flow alters arterial haemodynamics in both positive and negative ways. The purpose of this study was to determine the effect of spiral flow on haemodynamic changes in aorta-renal bifurcations. In this regard, a computational fluid dynamics analysis of pulsatile blood flow was performed in two idealised models of aorta-renal bifurcations with and without flow diverter. The results show that the spirality effect causes a substantial variation in blood velocity distribution, while causing only slight changes in fluid shear stress patterns. The dominant observed effect of spiral flow is on turbulent kinetic energy and flow recirculation zones. As spiral flow intensity increases, the rate of turbulent kinetic energy production decreases, reducing the region of potential damage to red blood cells and endothelial cells. Furthermore, the recirculation zones which form on the cranial sides of the aorta and renal artery shrink in size in the presence of spirality effect; this may lower the rate of atherosclerosis development and progression in the aorta-renal bifurcation. These results indicate that the spiral nature of blood flow has atheroprotective effects in renal arteries and should be taken into consideration in analyses of the aorta and renal arteries.

  3. Regional cerebral blood flow measurement in brain tumors

    International Nuclear Information System (INIS)

    Izunaga, Hiroshi; Hirota, Yoshihisa; Takahashi, Mutsumasa; Fuwa, Isao; Kodama, Takafumi; Matsukado, Yasuhiko

    1986-01-01

    The regional cerebral blood flow (CBF) was determined on seventeen patients with brain tumors. Ring type single photon emission CT (SPECT) was used following intravenous injection of 133 Xe. Case materials included eleven meningiomas and six malignant gliomas. Evaluation was performed with emphasis on the following points; 1. Correlation of the flow data within tumors to the angiographic tumor stains, 2. Influence of tumors on the cerebral blood flow of the normal brain tissue, 3. Correlation between degree of peripheral edema and the flow data of the affected hemispheres. There was significant correlation between flow data within tumors and angiographic tumor stains in meningiomas. Influence of tumors on cerebral blood flow of the normal tissue was greater in meningiomas than in gliomas. There was negative correlation between the degree of peripheral edema and the flow data of the affected hemisphere. It has been concluded that the measurement of CBF in brain tumors is a valuable method in evaluation of brain tumors. (author)

  4. Regional cerebral blood flow measurement in brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Izunaga, Hiroshi; Hirota, Yoshihisa; Takahashi, Mutsumasa; Fuwa, Isao; Kodama, Takafumi; Matsukado, Yasuhiko

    1986-10-01

    The regional cerebral blood flow (CBF) was determined on seventeen patients with brain tumors. Ring type single photon emission CT (SPECT) was used following intravenous injection of /sup 133/Xe. Case materials included eleven meningiomas and six malignant gliomas. Evaluation was performed with emphasis on the following points; 1. Correlation of the flow data within tumors to the angiographic tumor stains, 2. Influence of tumors on the cerebral blood flow of the normal brain tissue, 3. Correlation between degree of peripheral edema and the flow data of the affected hemispheres. There was significant correlation between flow data within tumors and angiographic tumor stains in meningiomas. Influence of tumors on cerebral blood flow of the normal tissue was greater in meningiomas than in gliomas. There was negative correlation between the degree of peripheral edema and the flow data of the affected hemisphere. It has been concluded that the measurement of CBF in brain tumors is a valuable method in evaluation of brain tumors.

  5. On the flow dependency of the electrical conductivity of blood

    NARCIS (Netherlands)

    Hoetink, AE; Faes, TJC; Visser, KR; Heethaar, RM

    Experiments presented in the literature show that the electrical conductivity of flowing blood depends on flow velocity. The aim of this study is to extend the Maxwell-Fricke theory, developed for a dilute suspension of ellipsoidal particles in an electrolyte, to explain this flow dependency of the

  6. Copper and ceruloplasmin contents in the blood serum of peripheral and pre-hepatic veins

    Directory of Open Access Journals (Sweden)

    H. M. Canelas

    1976-03-01

    Full Text Available Copper and ceruloplasmin contents were determined in samples of peripheral and pre-hepatic venous blood of 11 patients with Manson's schistosomiasis and one patient with hepatolenticular degeneration, all of çhich submitted either to porto-caval or spleno-renal shunt. Individual difference were not significant in any of the non-Wilsonian patients. The results are discussed in regard to the current knowledge on the pathogenesis of Wilson's disease.

  7. Regulation of Blood Flow in Contracting Skeletal Muscle in Aging

    DEFF Research Database (Denmark)

    Piil, Peter Bergmann

    Oxygen delivery to skeletal muscle is regulated precisely to match the oxygen demand; however, with aging the regulation of oxygen delivery during exercise is impaired. The present thesis investigated mechanisms underlying the age-related impairment in regulation of blood flow and oxygen delivery......GMP) was used as intervention, and skeletal muscle blood flow, oxygen delivery, and functional sympatholysis was examined. The two studies included 53 healthy, habitually active, male subjects. All subjects participated in an experimental day in which femoral arterial blood flow and blood pressure were assessed...... that improving sympatholytic capacity by training may be a slower process in older than in young men. In conclusion, this thesis provides new important knowledge related to the regulation of skeletal muscle blood flow in aging. Specifically, it demonstrates that changes in cGMP signaling is an underlying cause...

  8. Nasal mucosal blood flow after intranasal allergen challenge

    International Nuclear Information System (INIS)

    Holmberg, K.; Bake, B.; Pipkorn, U.

    1988-01-01

    The nasal mucosal blood flow in patients with allergic rhinitis was determined at nasal allergen challenges with the 133 Xenon washout method. Determinations were made in 12 subjects before and 15 minutes after challenge with diluent and increasing doses of allergen. The time course was followed in eight subjects by means of repeated measurements during 1 hour after a single allergen dose. Finally, the blood flow was measured after unilateral allergen challenge in the contralateral nasal cavity. A dose-dependent decrease in blood flow was found after nasal challenge with increasing doses of allergens, whereas challenge with diluent alone did not induce any changes. The highest allergen dose, which also induced pronounced nasal symptoms, resulted in a decrease in blood flow of 25% (p less than 0.001). The time-course study demonstrated a maximum decrease in blood flow 10 to 20 minutes after challenge and then a gradual return to baseline. Unilateral allergen challenge resulted in a decrease in blood flow in the contralateral, unchallenged nasal cavity, suggesting that part of the allergen-induced changes in blood flow were reflex mediated

  9. The role of blood flow in chronic duodenal ulcer

    Energy Technology Data Exchange (ETDEWEB)

    Gompertz, R.H.K.; Mathie, R.T.; Michalowski, A.S.; Spencer, J.; Baron, J.H.; Williamson, R.C.N.

    1996-01-01

    Changes in gastroduodenal blood flow have been implicated in the pathogenesis of duodenal ulcer. The authors have studied duodenal blood flow during the development of an acute to chronic duodenal ulcer by using the abscopal model, in which ulcers are generated as an indirect effect of lower mediastinal irradiation. Female CFLP mice were randomly allocated to one of three groups. Irradiated ``controls`` received 18 Gy 250 kV X-rays to the upper mediastinum. The lower mediastinum group received the same dose of irradiation, which has been shown to induce typical chronic duodenal ulcers in 45% of animals so treated. Animals were studied by means of radiolabelled microspheres 3 or 7 days later. Proximal duodenal blood flow specifically was reduced by 32% in the lower mediastinum group compared with irradiated controls at 7 days. There was no significant difference in blood flow to the stomach and to the distal duodenum. The decrease in proximal duodenal blood flow in the lower mediastinum group did not differ in the five animals that developed ulcer compared with the seven that did not. Although, there is an overall decrease in duodenal blood flow associated with chronic duodenal ulcer, reduced blood flow may not explain individual susceptibility to ulceration. 21 refs., 1 fig., 2 tabs.

  10. Increased bone marrow blood flow in polycythemia vera

    International Nuclear Information System (INIS)

    Lathinen, R.; Lathinen, T.; Hyoedynmaa, S.

    1983-01-01

    Bone marrow blood flow was measured in polycythemia vera, in compensatory and in relative polycythemia with a 133 Xe washout method. In the treated polycythemia vera bone marrow blood flow was significantly increased compared with the age-matched controls. The fraction of blood flow entering the bone and flowing through the hematopoietic marrow was markedly increased in both the untreated and the treated polycythemia vera. Although the number of observations in compensatory and relative polycythemia was small, the results suggest that bone marrow blood flow is not markedly increased in these diseases. The results also suggest that in older patients the simple 133 Xe method may support the diagnosis of polycythemia vera. (orig.)

  11. Increased bone marrow blood flow in polycythemia vera

    Energy Technology Data Exchange (ETDEWEB)

    Lathinen, R.; Lathinen, T.; Hyoedynmaa, S.

    1983-01-01

    Bone marrow blood flow was measured in polycythemia vera, in compensatory and in relative polycythemia with a /sup 133/Xe washout method. In the treated polycythemia vera bone marrow blood flow was significantly increased compared with the age-matched controls. The fraction of blood flow entering the bone and flowing through the hematopoietic marrow was markedly increased in both the untreated and the treated polycythemia vera. Although the number of observations in compensatory and relative polycythemia was small, the results suggest that bone marrow blood flow is not markedly increased in these diseases. The results also suggest that in older patients the simple /sup 133/Xe method may support the diagnosis of polycythemia vera.

  12. In-Situ Characterization of Tissue Blood Flow, Blood Content, and Water State Using New Techniques in Magnetic Resonance Imaging.

    Science.gov (United States)

    Conturo, Thomas Edward

    Tissue blood flow, blood content, and water state have been characterized in-situ with new nuclear magnetic resonance imaging techniques. The sensitivities of standard techniques to the physiologic tissue parameters spin density (N_{rm r}) and relaxation times (T_1 and T_2 ) are mathematically defined. A new driven inversion method is developed so that tissue T_1 and T_2 changes produce cooperative intensity changes, yielding high contrast, high signal to noise, and sensitivity to a wider range of tissue parameters. The actual tissue parameters were imaged by automated collection of multiple-echo data having multiple T _1 dependence. Data are simultaneously fit by three-parameters to a closed-form expression, producing lower inter-parameter correlation and parameter noise than in separate T_1 or T_2 methods or pre-averaged methods. Accurate parameters are obtained at different field strengths. Parametric images of pathology demonstrate high sensitivity to tissue heterogeneity, and water content is determined in many tissues. Erythrocytes were paramagnetically labeled to study blood content and relaxation mechanisms. Liver and spleen relaxation were enhanced following 10% exchange of animal blood volumes. Rapid water exchange between intracellular and extracellular compartments was validated. Erythrocytes occupied 12.5% of renal cortex volume, and blood content was uniform in the liver, spleen and kidney. The magnitude and direction of flow velocity was then imaged. To eliminate directional artifacts, a bipolar gradient technique sensitized to flow in different directions was developed. Phase angle was reconstructed instead of intensity since the former has a 2pi -fold higher dynamic range. Images of flow through curves demonstrated secondary flow with a centrifugally-biased laminar profile and stationary velocity peaks along the curvature. Portal vein flow velocities were diminished or reversed in cirrhosis. Image artifacts have been characterized and removed. The

  13. Experimental studies of renal blood flow by digitized functional angiography

    International Nuclear Information System (INIS)

    Buersch, J.H.; Ochs, C.; Hahne, H.J.; Heintzen, P.H.

    1985-01-01

    New techniques of digital image processing have been experimentally tested for the assessment of renal blood flow. The underlying principle in functional angiography is the extraction of flow parameters. Basically, density-time variations of the contrast medium are analayzed from to each picture element of a 256x256 matrix. The real-time acquisition rate of images was 25/sec. For the calculation of angiographic flow a PDP 11/40 computer was used to interactively perform a time dependent segmentation of the renal arteries and the aorta. Subsequently, volume flow was calculated in relative units for the specific vascular segments under study. 15 control angiograms were made in 5 animals with cardiac output ranging between 0.8 to 2.2l/min. Unilateral renal blood flow was calculated as 24+-3.4% of pre-renal aortic flow without systematic side differences. Reproducibility from repeated flow measurements showed an SD of +-1.8% of the individual pre-renal aortic flow. Renal flow was also measured in 3 animals with an experimentally created 50% flow reduction of the left kidney. Angiographic flow in the left renal artery dropped to 12+-2% of pre-renal flow. The present experimental data suggest that digital angiography has sufficient diagnostic capabilities for the detection of abnormal renal blood flow. The technique may serve as a useful diagnostic adjunct to conventional angiography and has the potential of assisting in the evaluation of renal vascular hypertension. (orig.) [de

  14. Velocity Estimation of the Main Portal Vein with Transverse Oscillation

    DEFF Research Database (Denmark)

    Brandt, Andreas Hjelm; Hansen, Kristoffer Lindskov; Nielsen, Michael Bachmann

    2015-01-01

    This study evaluates if Transverse Oscillation (TO) can provide reliable and accurate peak velocity estimates of blood flow the main portal vein. TO was evaluated against the recommended and most widely used technique for portal flow estimation, Spectral Doppler Ultrasound (SDU). The main portal...

  15. Collateral sources of costal and crural diaphragmatic blood flow

    International Nuclear Information System (INIS)

    Lockhat, D.; Magder, S.; Roussos, C.

    1985-01-01

    We measured the contribution of aortic, internal mammary, and intercostal arteries to the blood flow to the costal and crural segments of the diaphragm and other respiratory muscles in seven dogs breathing against a fixed inspiratory elastic load. We used radiolabeled microspheres to measure the blood flow with control circulation, occlusion of the aorta distal to the left subclavian artery, combined occlusion of the aorta and both internal mammary arteries, and occlusion of internal mammary arteries alone. With occlusion of the aorta distal to the left subclavian artery, blood flow to the crural diaphragm decreased from 40.3 to 23.5 ml . min-1 X 100 g-1, whereas costal flow did not change significantly (from 41.7 to 38.1 ml . min-1 . 100 g-1). Blood flows to the sternomastoid and scalene muscles (above the occlusion) increased by 200 and 340%, respectively, whereas flows to the other respiratory muscles did not change significantly. Blood flows to organs above the occlusion either remained unchanged or increased, whereas flows to those below the occlusion all decreased. When the internal mammary artery was also occluded, flows to the crural segment decreased further to 12.1 and costal flow decreased to 20.4 ml X min-1 X 100 g-1. Internal mammary arterial occlusion alone in two dogs had no effect on diaphragmatic flow. In conclusion, intercostal collateral vessels are capable of supplying a significant proportion of blood flow to both segments of the diaphragm but the costal segment is better served than the crural segment

  16. Comparison of L-lysine aescinat and Kontrikal blood flow and morphology of the vessel in the brain is awake rabbits general vibration

    Directory of Open Access Journals (Sweden)

    A. G. Belyakova

    2013-02-01

    Full Text Available Chronic experiments on conscious rabbits with needle-shaped platinum electrodes implanted into the brain cortex, thalamus and hypothalamus were made. The modeling of wide-frequency vibration causes slowing down of cerebral blood flow. L-lysine aescinat prevents changing of blood flow in hypothalamus, causes growth into the brain cortex and not significant lowering in thalamus. Contrykal provides absolute growth of a blood circulation in all structures that were studied. In acute experiments on conscious rabbits wide-frequency vibration causes spasm arterioles and dilation of veins. According to histologic dates L-lysine aescinat prevents changes in the bloodstream better than Contrykal.

  17. Muscle blood flow at onset of dynamic exercise in humans.

    Science.gov (United States)

    Rådegran, G; Saltin, B

    1998-01-01

    To evaluate the temporal relationship between blood flow, blood pressure, and muscle contractions, we continuously measured femoral arterial inflow with ultrasound Doppler at onset of passive exercise and voluntary, one-legged, dynamic knee-extensor exercise in humans. Blood velocity and inflow increased (P dicrotic and diastolic blood pressure notches, respectively. Mechanical hindrance occurred (P dicrotic notch. The increase in blood flow (Q) was characterized by a one-component (approximately 15% of peak power output), two-component (approximately 40-70% of peak power output), or three-component exponential model (> or = 75% of peak power output), where Q(t) = Qpassive + delta Q1.[1 - e-(t - TD1/tau 1)]+ delta Q2.[1 - e-(t - TD2/tau 2)]+ delta Q3.[1 - e-(t - TD3/tau 3)]; Qpassive, the blood flow during passive leg movement, equals 1.17 +/- 0.11 l/min; TD is the onset latency; tau is the time constant; delta Q is the magnitude of blood flow rise; and subscripts 1-3 refer to the first, second, and third components of the exponential model, respectively. The time to reach 50% of the difference between passive and voluntary asymptotic blood flow was approximately 2.2-8.9 s. The blood flow leveled off after approximately 10-150 s, related to the power outputs. It is concluded that the elevation in blood flow with the first duty cycle(s) is due to muscle mechanical factors, but vasodilators initiate a more potent amplification within the second to fourth contraction.

  18. CD4+ LYMPHOCYTES IMPROVE VENOUS BLOOD FLOW IN EXPERIMENTAL ARTERIOVENOUS FISTULAE

    Science.gov (United States)

    Duque, Juan C.; Martinez, Laisel; Mesa, Annia; Wei, Yuntao; Tabbara, Marwan; Salman, Loay H.; Vazquez-Padron, Roberto I.

    2015-01-01

    Background The role of immune cells in arteriovenous fistulae (AVF) maturation is poorly understood and has received, until quite recently, little attention. This study examines the role of T lymphocytes in AVF vascular remodeling. Methods Experimental fistulae were created in athymic rnu nude rats lacking mature T lymphocytes and euthymic control animals by anastomosing the left superior epigastric vein to the nearby femoral artery. Blood flow rates, wall morphology and histological changes were assessed in AVF 21 days after creation. The effect of CD4+ lymphocytes on AVF maturation in athymic animals was analyzed by adoptive transfer of cells after fistula creation. Results The absence of T lymphocytes compromised blood flow in experimental fistulae. Histopathological inspection of AVF from athymic rats revealed that T cell immunodeficiency negatively affected venous vascular remodeling, as evidenced by a reduced lumen, a thick muscular layer and a low number of inflammatory cells compared to control animals. Adoptive transfer of CD4+ lymphocytes from euthymic rats into athymic animals before and after fistula creation improved blood flow and reduced intima-media thickness. Conclusion These results point at the protective role of CD4+ lymphocytes in the remodeling of the AVF vascular wall. PMID:25999254

  19. Doppler ultrasonographic measurement of short-term effects of valsalva maneuver on retrobulbar blood flow.

    Science.gov (United States)

    Kimyon, Sabit; Mete, Ahmet; Mete, Alper; Mete, Duçem

    2017-11-12

    To investigate the effects of Valsalva maneuver (VM) on retrobulbar blood flow parameters in healthy subjects. Participants without any ophthalmologic or systemic pathology were examined in supine position with color and pulsed Doppler imaging for blood flow measurement, via a paraocular approach, in the ophthalmic artery (OA), central retinal artery (CRA), central retinal vein (CRV), nasal posterior ciliary artery (NPCA), and temporal posterior ciliary artery (TPCA), 10 seconds after a 35- to 40-mm Hg expiratory pressure was reached. Peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and resistivity index (RI) values were recorded for each artery. PSV and EDV values were recorded for CRV. There were significant differences between resting and VM values of PSV and EDV of CRA, RI of NPCA, and PI, RI, and EDV of TPCA. Resting CRA-EDV, CRV-PSV, and CRV-EDV were positively correlated whereas resting OA-PSV and CRA-PI, and OA-PSV, CRA-PSV, and CRA-EDV during VM, were negatively correlated with age. VM induces a short-term increase in CRA blood flow and a decrease in NPCA and TPCA RI. Additional studies with a longer Doppler recording during VM, in a larger population sample, are required to allow definitive interpretation. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:551-555, 2017. © 2017 Wiley Periodicals, Inc.

  20. Simulation, Fabrication and Analysis of Silver Based Ascending Sinusoidal Microchannel (ASMC for Implant of Varicose Veins

    Directory of Open Access Journals (Sweden)

    Muhammad Javaid Afzal

    2017-09-01

    Full Text Available Bioengineered veins can benefit humans needing bypass surgery, dialysis, and now, in the treatment of varicose veins. The implant of this vein in varicose veins has significant advantages over the conventional treatment methods. Deep vein thrombosis (DVT, vein patch repair, pulmonary embolus, and tissue-damaging problems can be solved with this implant. Here, the authors have proposed biomedical microdevices as an alternative for varicose veins. MATLAB and ANSYS Fluent have been used for simulations of blood flow for bioengineered veins. The silver based microchannel has been fabricated by using a micromachining process. The dimensions of the silver substrates are 51 mm, 25 mm, and 1.1 mm, in length, width, and depth respectively. The dimensions of microchannels grooved in the substrates are 0.9 mm in width and depth. The boundary conditions for pressure and velocity were considered, from 1.0 kPa to 1.50 kPa, and 0.02 m/s to 0.07 m/s, respectively. These are the actual values of pressure and velocity in varicose veins. The flow rate of 5.843 (0.1 nL/s and velocity of 5.843 cm/s were determined at Reynolds number 164.88 in experimental testing. The graphs and results from simulations and experiments are in close agreement. These microchannels can be inserted into varicose veins as a replacement to maintain the excellent blood flow in human legs.

  1. Anatomic and hemodynamic evaluation of renal venous flow in varicocele formation using color Doppler sonography with emphasis on renal vein entrapment syndrome.

    Science.gov (United States)

    Unlu, Murat; Orguc, Sebnem; Serter, Selim; Pekindil, Gokhan; Pabuscu, Yuksel

    2007-01-01

    To investigate the anatomic and hemodynamic properties of testicular venous drainage and its effects on varicocele formation and reflux using color Doppler ultrasound (US) with emphasis on renal vein entrapment syndrome. Upper abdominal and scrotal US examinations of 35 varicocele patients and 35 healthy male subjects were performed in the supine position during rest, during a Valsalva maneuver and in the erect position. The aortomesenteric angle and distance (AMA and AMD, respectively), peak mean velocities (PVs) and diameters of different segments of renal veins, testicular vein diameters and duration of flow inversion were measured. In the varicocele group, the lateral segment of the left renal vein (LRV) had a larger diameter and slower PV, and the medial segment of the LRV had a smaller diameter and faster PV. The diameter of the dominant draining vein correlated with the PV of the medial and lateral segments of the LRV, whereas there was no correlation between the diameter of the dominant draining vein and the diameters of the right renal vein (RRV) and the lateral segment of the LRV or the PV of the RRV. The duration of flow inversion correlated with the diameter and PV of the medial segment of the LRV. No correlation between the diameters and PVs of the RRV and the lateral segment of the LRV was detected. The decreases in the AMA, AMD, diameter of the medial segment of the LRV and PV of the lateral segment of the LRV, and the increases in the PV of the medial segment of the LRV and the diameter of the lateral segment of the LRV in varicocele patients in all positions suggest the entrapment or impingement of the left renal vein between the aorta and the superior mesenteric artery. This has been defined as the "nutcracker phenomenon", which is known to affect varicocele formation.

  2. Local viscosity distribution in bifurcating microfluidic blood flows

    Science.gov (United States)

    Kaliviotis, E.; Sherwood, J. M.; Balabani, S.

    2018-03-01

    The red blood cell (RBC) aggregation phenomenon is majorly responsible for the non-Newtonian nature of blood, influencing the blood flow characteristics in the microvasculature. Of considerable interest is the behaviour of the fluid at the bifurcating regions. In vitro experiments, using microchannels, have shown that RBC aggregation, at certain flow conditions, affects the bluntness and skewness of the velocity profile, the local RBC concentration, and the cell-depleted layer at the channel walls. In addition, the developed RBC aggregates appear unevenly distributed in the outlets of these channels depending on their spatial distribution in the feeding branch, and on the flow conditions in the outlet branches. In the present work, constitutive equations of blood viscosity, from earlier work of the authors, are applied to flows in a T-type bifurcating microchannel to examine the local viscosity characteristics. Viscosity maps are derived for various flow distributions in the outlet branches of the channel, and the location of maximum viscosity magnitude is obtained. The viscosity does not appear significantly elevated in the branches of lower flow rate as would be expected on the basis of the low shear therein, and the maximum magnitude appears in the vicinity of the junction, and towards the side of the outlet branch with the higher flow rate. The study demonstrates that in the branches of lower flow rate, the local viscosity is also low, helping us to explain why the effects of physiological red blood cell aggregation have no adverse effects in terms of in vivo vascular resistance.

  3. Arterial secondary blood flow patterns visualized with vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Hansen, Jens Munk

    2011-01-01

    This study presents the first quantification and visualisation of secondary flow patterns with vector flow ultrasound. The first commercial implementation of the vector flow method Transverse Oscillation was used to obtain in-vivo, 2D vector fields in real-time. The hypothesis of this study...... was that the rotational direction is constant within each artery. Three data sets of 10 seconds were obtained from three main arteries in healthy volunteers. For each data set the rotational flow patterns were identified during the diastole. Each data set contains a 2D vector field over time and with the vector angles...

  4. Low cerebral blood flow in hypotensive perinatal distress

    International Nuclear Information System (INIS)

    Lou, H.C.; Lassen, N.A.; Friis-Hansen, B.

    1977-01-01

    Hypoxic brain injury is the most important neurological problem in the neonatal period and accounts for more neurological deficits in children than any other lesion. The neurological deficits are notably mental retardation, epilepsy and cerebral palsy. The pathogenesis has hitherto been poorly understood. Arterial hypoxia has been taken as the obvious mechanism but this does not fully explain the patho-anatomical findings. In the present investigation we have examined the arterial blood pressure and the cerebral blood flow in eight infants a few hours after birth. The 133Xe clearance technique was used for the cerebral blood flow measurements. The study confirmed that perinatal distress may be associated with low arterial blood pressure, and it was shown that cerebral blood flow is very low, 20 ml/100 g/min or less, in hypotensive perinatal distress. It is concluded that cerebral ischaemia plays a crucial role in the development of perinatal hypoxic brain injury. (author)

  5. Aging, regional cerebral blood flow, and neuropsychological functioning

    International Nuclear Information System (INIS)

    MacInnes, W.D.; Golden, C.J.; Gillen, R.W.; Sawicki, R.F.; Quaife, M.; Uhl, H.S.; Greenhouse, A.J.

    1984-01-01

    Previous studies found changes in regional cerebral blood flow (rCBF) patterns related to both age and various cognitive tasks. However, no study has yet demonstrated a relationship between rCBF and performance on the Luria-Nebraska Neuropsychological Battery (LNNB) in an elderly group. Seventy-nine elderly volunteers (56-88 years old), both healthy and demented, underwent the 133 xenon inhalation rCBF procedure and were given the LNNB. The decrements in the gray-matter blood flow paralleled decrements in performance on the LNNB. Using partial correlations, a significant proportion of shared variance was observed between gray-matter blood flow and the LNNB scales. However, there was much less of a relationship between white-matter blood flow and performance on the LNNB. This study suggests that even within a restricted age sample rCBF is related in a global way to neuropsychological functioning

  6. Dynamic emission tomography of regional cerebral blood flow

    International Nuclear Information System (INIS)

    Lassen, N.A.

    1984-01-01

    The author reviews three tomographic methods for measuring the regional cerebral blood flow: single photon transmission tomography; dual photon emission tomography; and single photon emission tomography. The latter technique is discussed in detail. (Auth.)

  7. Patient Specific Multiscale Simulations of Blood Flow in Coronary Artery Bypass Surgery

    Science.gov (United States)

    Bangalore Ramachandra, Abhay; Sankaran, Sethuraman; Kahn, Andrew M.; Marsden, Alison L.

    2013-11-01

    Coronary artery bypass surgery is performed to revascularize blocked coronary arteries in roughly 400,000 patients per year in the US.While arterial grafts offer superior patency, vein grafts are used in more than 70% of procedures, as most patients require multiple grafts. Vein graft failure (approx. 50% within 10 years) remains a major clinical issue. Mounting evidence suggests that hemodynamics plays a key role as a mechano-biological stimulus contributing to graft failure. However, quantifying relevant hemodynamic quantities (e.g. wall shear stress) invivo is not possible directly using clinical imaging techniques. We numerically compute graft hemodynamics in a cohort of 3-D patient specific models using a stabilized finite element method. The 3D flow domain is coupled to a 0D lumped parameter circulatory model. Boundary conditions are tuned to match patient specific blood pressures, stroke volumes & heart rates. Results reproduce clinically observed coronary flow waveforms. We quantify differences in multiple hemodynamic quantities between arterial & venous grafts & discuss possible correlations between graft hemodynamics & clinically observed graft failure.Such correlations will provide further insight into mechanisms of graft failure and may lead to improved clinical outcomes.

  8. Temperature and blood flow distribution in the human leg during passive heat stress.

    Science.gov (United States)

    Chiesa, Scott T; Trangmar, Steven J; González-Alonso, José

    2016-05-01

    The influence of temperature on the hemodynamic adjustments to direct passive heat stress within the leg's major arterial and venous vessels and compartments remains unclear. Fifteen healthy young males were tested during exposure to either passive whole body heat stress to levels approaching thermal tolerance [core temperature (Tc) + 2°C; study 1; n = 8] or single leg heat stress (Tc + 0°C; study 2; n = 7). Whole body heat stress increased perfusion and decreased oscillatory shear index in relation to the rise in leg temperature (Tleg) in all three major arteries supplying the leg, plateauing in the common and superficial femoral arteries before reaching severe heat stress levels. Isolated leg heat stress increased arterial blood flows and shear patterns to a level similar to that obtained during moderate core hyperthermia (Tc + 1°C). Despite modest increases in great saphenous venous (GSV) blood flow (0.2 l/min), the deep venous system accounted for the majority of returning flow (common femoral vein 0.7 l/min) during intense to severe levels of heat stress. Rapid cooling of a single leg during severe whole body heat stress resulted in an equivalent blood flow reduction in the major artery supplying the thigh deep tissues only, suggesting central temperature-sensitive mechanisms contribute to skin blood flow alone. These findings further our knowledge of leg hemodynamic responses during direct heat stress and provide evidence of potentially beneficial vascular alterations during isolated limb heat stress that are equivalent to those experienced during exposure to moderate levels of whole body hyperthermia. Copyright © 2016 the American Physiological Society.

  9. Retinal oximetry during treatment of retinal vein occlusion by ranibizumab in patients with high blood pressure and dyslipidemia.

    Science.gov (United States)

    Keilani, C; Halalchi, A; Wakpi Djeugue, D; Regis, A; Abada, S

    2016-12-01

    In the present study, we examined retinal vascular oxygen saturation in patients with retinal vein occlusion (RVO), high blood pressure (HBP) and dyslipidemia, before and during intravitreal vascular endothelial growth factor (VEGF) injection (ranibizumab). We retrospectively reviewed the medical records of six patients with visual acuity (VA) reduced by macular edema (ME) secondary to RVO with HBP and dyslipidemia, who underwent intravitreal anti-VEGF injection between October 2014 and February 2015 in the department of ophthalmology of François-Quesnay Hospital at Mantes-la-Jolie (France). The main inclusion criterion was the presence of RVO with ME and decreased VA. The primary endpoint was improvement of retinal venous oxygen saturation in patients with RVO before and 3 months after intravitreal ranibizumab injection. Secondary outcomes were improvement of retinal arterial oxygen saturation, improvement of best-corrected visual acuity (BCVA) on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale, regression of ME measured by the central macular thickness (CMT) in nm and studying the correlation between blood pressure (BP) and retinal venous oxygen saturation before and after ranibizumab. Six eyes of six patients were included. Before treatment, the mean (standard deviation [SD]) of the retinal venous saturation (%) was 38.1±14.2. Three months after the injections, the mean (SD) of the retinal venous saturation (%) increased statistically significantly 49.2±11 (P=0.03). In this study, retinal venous oxygen saturation in patients with RVO, HBP and dyslipidemia was partially normalized during intravitreal ranibizumab treatment. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  10. Pulsed cavitational therapy using high-frequency ultrasound for the treatment of deep vein thrombosis in an in vitro model of human blood clot

    Science.gov (United States)

    Goudot, G.; Mirault, T.; Arnal, B.; Boisson-Vidal, C.; Le Bonniec, B.; Gaussem, P.; Galloula, A.; Tanter, M.; Messas, E.; Pernot, M.

    2017-12-01

    Post-thrombotic syndrome, a frequent complication of deep venous thrombosis, can be reduced with early vein recanalization. Pulsed cavitational therapy (PCT) using ultrasound is a recent non-invasive approach. We propose to test the efficacy and safety of high-frequency focused PCT for drug-free thrombolysis (thrombotripsy) in a realistic in vitro model of venous thrombosis. To reproduce venous thrombosis conditions, human whole blood was allowed to clot by stasis in silicone tubes (6 mm internal diameter) at a 30 cm H2O pressure, maintained during the whole experiment. We engineered an ultrasound device composed of dual 2.25 MHz transducers centered around a 6 MHz imaging probe. A therapeutic focus was generated at a 3.2 cm depth from the probe. Thrombotripsy was performed by longitudinally scanning the thrombus at three different speeds: 1 mm s-1 (n  =  6) 2 mm s-1 (n  =  6) 3 mm s-1 (n  =  12). Restored outflow was measured every three passages. Filters were placed to evaluate the debris size. Twenty-four occlusive thrombi, of 2.5 cm mean length and 4.4 kPa mean stiffness, were studied. Flow restoration was systematically obtained by nine subsequent passages (4.5 min maximum). By varying the device’s speed, we found an optimal speed of 1 mm s-1 to be efficient for effective recanalization with 90 s (three passages). Within 90 s, flow restoration was of 80, 62 and 74% at respectively 1, 2 and 3 mm s-1. For all groups, cavitation cloud drilled a 1.7 mm mean diameter channel throughout the clot. Debris analysis showed 92% of debris    200 µm.

  11. Effect of tropicamide on ocular blood flow in the rabbit

    International Nuclear Information System (INIS)

    Delgado, D.; Michel, P.; Jaanus, S.D.

    1982-01-01

    Intracardiac injection of 15 microspheres labeled with 85 Sr (strontium) and 141 Ce (cerium) were used to determine ocular blood flow in seven rabbits before and 25 min after bilateral application of tropicamide to the cornea. By using two different isotopes distinguishable under gammaspectrometry, each animal served as its own control. After administration of two drops of 1% tropicamide, no significant difference in blood flow between treated and untreated eyes was observed

  12. Chronic Stress Impairs Collateral Blood Flow Recovery in Aged Mice

    Science.gov (United States)

    2014-10-15

    of oxidative stress in atherosclerosis. American of Journal in Cardiology , 91, 7A–11A. 11. Balkaya, M., Prinz, V., Custodis, F., et al. (2011...femoral artery occlusion (Figs. 2 and 5). Fig. 2 Blood flow recovery measurement after FAL. Blood flow mea- sured for control ( open circle) and stressed...peripheral arterial disease. Journal General and International Medication, 18(6), 461–467. 5. Yan, L. L., Liu, K., Matthews, K. A., et al. (2003). Psychosocial

  13. Blood flow rate measurements with indicator techniques revisited

    DEFF Research Database (Denmark)

    Sejrsen, Per; Bülow, Jens

    2009-01-01

    In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions......, necessary precautions for the application of these experimental techniques are emphasized. Special attention has been carried out to elucidate the consequence of a choice of indicators having a large distribution volume in the tissues....

  14. Non-invasive pulmonary blood flow analysis and blood pressure mapping derived from 4D flow MRI

    Science.gov (United States)

    Delles, Michael; Rengier, Fabian; Azad, Yoo-Jin; Bodenstedt, Sebastian; von Tengg-Kobligk, Hendrik; Ley, Sebastian; Unterhinninghofen, Roland; Kauczor, Hans-Ulrich; Dillmann, Rüdiger

    2015-03-01

    In diagnostics and therapy control of cardiovascular diseases, detailed knowledge about the patient-specific behavior of blood flow and pressure can be essential. The only method capable of measuring complete time-resolved three-dimensional vector fields of the blood flow velocities is velocity-encoded magnetic resonance imaging (MRI), often denoted as 4D flow MRI. Furthermore, relative pressure maps can be computed from this data source, as presented by different groups in recent years. Hence, analysis of blood flow and pressure using 4D flow MRI can be a valuable technique in management of cardiovascular diseases. In order to perform these tasks, all necessary steps in the corresponding process chain can be carried out in our in-house developed software framework MEDIFRAME. In this article, we apply MEDIFRAME for a study of hemodynamics in the pulmonary arteries of five healthy volunteers. The study included measuring vector fields of blood flow velocities by phase-contrast MRI and subsequently computing relative blood pressure maps. We visualized blood flow by streamline depictions and computed characteristic values for the left and the right pulmonary artery (LPA and RPA). In all volunteers, we observed a lower amount of blood flow in the LPA compared to the RPA. Furthermore, we visualized blood pressure maps using volume rendering and generated graphs of pressure differences between the LPA, the RPA and the main pulmonary artery. In most volunteers, blood pressure was increased near to the bifurcation and in the proximal LPA, leading to higher average pressure values in the LPA compared to the RPA.

  15. Corticosteroid Reduces Blood Flow to Femoral Heads in Rabbits.

    Science.gov (United States)

    Hou, S.M.; Liu, T.K.; Kao, M.C.

    1994-12-01

    Avascular necrosis of the femoral head is one of the common problems in orthopedic practice in Taiwan. The subchondral bone loses its blood supply which weakens its biomechanical support. Steroid overuse is one of many possible etiologies in reducing blood flow to the femoral head. Laser Doppler velocimeter is a precise monitor of regional blood flow of bone which is expressed in perfusion units (PU). In the control group the rabbits were injected with normal saline and there were no statistical differences between blood flow to the right hip (39.26 +/- 5.64 PU) and left hip (38.58 +/- 4.35 PU). In group B a weekly injection of methylprednisolone into rabbits for 6 weeks demonstrated the reduction of blood flow of femoral head (24.74 +/- 3.13 PU) by the laser Doppler velocimeter. The flow decreased further (15.93 +/- 2.33 PU) by 12 weeks of steroid treatment. In group C after a weekly injection of steroid for 6 weeks the flow became 31.63 +/- 4.79 PU. The steroid was then discontinued for 3 weeks and the flow was 34.6 +/- 1.34 PU. In group D the blood flow was 25.89 +/- 4.01 PU after 6 weeks of steroid treatment and we stopped the steroid for 6 weeks, the blood flow became 29.86 +/- 2.59 PU. The merit of our experiment established a model of study in avascular necrosis of the femoral head in rabbits. Copyright 1994 S. Karger AG, Basel

  16. Establishing the diffuse correlation spectroscopy signal relationship with blood flow.

    Science.gov (United States)

    Boas, David A; Sakadžić, Sava; Selb, Juliette; Farzam, Parisa; Franceschini, Maria Angela; Carp, Stefan A

    2016-07-01

    Diffuse correlation spectroscopy (DCS) measurements of blood flow rely on the sensitivity of the temporal autocorrelation function of diffusively scattered light to red blood cell (RBC) mean square displacement (MSD). For RBCs flowing with convective velocity [Formula: see text], the autocorrelation is expected to decay exponentially with [Formula: see text], where [Formula: see text] is the delay time. RBCs also experience shear-induced diffusion with a diffusion coefficient [Formula: see text] and an MSD of [Formula: see text]. Surprisingly, experimental data primarily reflect diffusive behavior. To provide quantitative estimates of the relative contributions of convective and diffusive movements, we performed Monte Carlo simulations of light scattering through tissue of varying vessel densities. We assumed laminar vessel flow profiles and accounted for shear-induced diffusion effects. In agreement with experimental data, we found that diffusive motion dominates the correlation decay for typical DCS measurement parameters. Furthermore, our model offers a quantitative relationship between the RBC diffusion coefficient and absolute tissue blood flow. We thus offer, for the first time, theoretical support for the empirically accepted ability of the DCS blood flow index ([Formula: see text]) to quantify tissue perfusion. We find [Formula: see text] to be linearly proportional to blood flow, but with a proportionality modulated by the hemoglobin concentration and the average blood vessel diameter.

  17. The clinical use of the device for flowing blood irradiation

    International Nuclear Information System (INIS)

    Arutyunov, A.S.; Karasev, A.B.; Kovalev, O.I.; Pisarevskij, A.A.; Skobennikov, A.K.; Trofimov, V.I.; Khaskel'berg, N.G.

    1988-01-01

    The indications and possibilities of using the device for flowing extracorporeal ultraviolet radiation of blood are considered. The uniformity of the radiation of blood in the proposed device provides an annular gap of the quartz dish with the partition in the shape of a spiral. It makes it possible to expose a larger part of the blood content of an organism simultaneously making use of various perfused methods of its detoxication

  18. Quantitative assessment of limb blood flow using Tc-99m labeled red blood cells

    International Nuclear Information System (INIS)

    Itoh, Kazuo; Shougase, Takashi; Kawamura, Naoyuki; Tsukamoto, Eriko; Nakada, Kunihiro; Sakuma, Makoto; Furudate, Masayori

    1987-01-01

    A quantitative assessment of limb blood flow using a non-diffusible radioindicator, Tc-99m labeled red blood cells, was reported. This was an application of venous occlusion plethysmography using radionuclide which was originally proposed by M. Fukuoka et al. The peripheral blood flow (mean ± s.e.) of 30 legs in a normal control group was 1.87 ± 0.08 ml/100 ml/min. In heart diseases (46 legs), it was 1.49 ± 0.13 ml/100 ml/min. The limb blood flow between a control group and heart diseases was statistically significant (p < 0.01) in the t-test. The peripheral blood flow at rest between diseased legs and normal legs in occlusive arterial disorders was also statistically significant (p < 0.01) in a paired t-test. RAVOP was done after the completion of objective studies such as radionuclide angiography or ventriculography. Technique and calculation of a blood flow were very easy and simple. RAVOP study which was originally proposed by Fukuoka et al. was reappraised to be hopeful for quantitative measurement of limb blood flow as a non-invasive technique using Tc-99m labeled red blood cells. (author)

  19. Black-blood thrombus imaging (BTI): a contrast-free cardiovascular magnetic resonance approach for the diagnosis of non-acute deep vein thrombosis.

    Science.gov (United States)

    Xie, Guoxi; Chen, Hanwei; He, Xueping; Liang, Jianke; Deng, Wei; He, Zhuonan; Ye, Yufeng; Yang, Qi; Bi, Xiaoming; Liu, Xin; Li, Debiao; Fan, Zhaoyang

    2017-01-18

    Deep vein thrombosis (DVT) is a common but elusive illness that can result in long-term disability or death. Accurate detection of thrombosis and assessment of its size and distribution are critical for treatment decision-making. In the present study, we sought to develop and evaluate a cardiovascular magnetic resonance (CMR) black-blood thrombus imaging (BTI) technique, based on delay alternating with nutation for tailored excitation black-blood preparation and variable flip angle turbo-spin-echo readout, for the diagnosis of non-acute DVT. METHODS: This prospective study was approved by institutional review board and informed consent obtained from all subjects. BTI was first conducted in 11 healthy subjects for parameter optimization and then conducted in 18 non-acute DVT patients to evaluate its diagnostic performance. Two clinically used CMR techniques, contrast-enhanced CMR venography (CE-MRV) and three dimensional magnetization prepared rapid acquisition gradient echo (MPRAGE), were also conducted in all patients for comparison. All images obtained from patients were analyzed on a per-segment basis. Using the consensus diagnosis of CE-MRV as the reference, the sensitivity (SE), specificity (SP), positive and negative predictive values (PPV and NPV), and accuracy (ACC) of BTI and MPRAGE as well as their diagnostic agreement with CE-MRV were calculated. Besides, diagnostic confidence and interreader diagnostic agreement were evaluated for all three techniques. BTI with optimized parameters effectively nulled the venous blood flow signal and allowed directly visualizing the thrombus within the black-blood lumen. Higher SE (90.4% vs 67.6%), SP (99.0% vs. 97.4%), PPV (95.4% vs. 85.6%), NPV (97.8% vs 92.9%) and ACC (97.4% vs. 91.8%) were obtained by BTI in comparison with MPRAGE. Good diagnostic confidence and excellent diagnostic and interreader agreements were achieved by BTI, which were superior to MPRAGE on detecting the chronic thrombus. BTI allows

  20. Changes in Hepatic Blood Flow During Transcatheter Arterial Infusion with Heated Saline in Hepatic VX2 Tumor

    International Nuclear Information System (INIS)

    Cao Wei; Li Jing; Wu Zhiqun; Zhou Changxi; Liu Xi; Wan Yi; Duan Yunyou

    2013-01-01

    Purpose. This study evaluates the influence of transcatheter arterial infusion with heated saline on hepatic arterial and portal venous blood flows to tumor and normal hepatic tissues in a rabbit VX2 tumor model. Methods. All animal experiments were approved by the institutional animal care and use committee. Twenty rabbits with VX2 liver tumors were divided into the following two groups: (a) the treated group (n = 10), which received a 60 mL transarterial injection of 60 °C saline via the hepatic artery; (b) the control group (n = 10), which received a 60 mL injection of 37 °C saline via the hepatic artery. Using ultrasonography, the blood flows in both the portal vein and hepatic artery were measured, and the changes in the hemodynamic indices were recorded before and immediately after the injection. The changes in the tumor and normal liver tissues of the two groups were histopathologically examined by hematoxylin and eosin staining after the injection. Results. After the transcatheter arterial heated infusion, there was a decrease in the hepatic arterial blood flow to the tumor tissue, a significant decrease in the hepatic artery mean velocity (P < 0.05), and a significant increase in the resistance index (P < 0.05). On hematoxylin and eosin staining, there were no obvious signs of tissue destruction in the normal liver tissue or the tumor tissue after heated perfusion, and coagulated blood plasma was observed in the cavities of intratumoral blood vessels in the treated group. Conclusions. The changes in tumor blood flow in the rabbit VX2 tumor model were presumably caused by microthrombi in the tumor vessels, and the portal vein likely mediated the heat loss in normal liver tissue during the transarterial heated infusion.

  1. Changes in Hepatic Blood Flow During Transcatheter Arterial Infusion with Heated Saline in Hepatic VX2 Tumor

    Energy Technology Data Exchange (ETDEWEB)

    Cao Wei, E-mail: cawe-001@163.com [Tangdu Hospital, The Fourth Military Medical University, Department of Interventional Radiology (China); Li Jing, E-mail: lijing02@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Burn and Plastic Surgery (China); Wu Zhiqun, E-mail: zhiqunwu@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Interventional Radiology (China); Zhou Changxi, E-mail: changxizhou@163.com [Chinese PLA General Hospital, Department of Respiratory Disease (China); Liu Xi, E-mail: xiliu@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Ultrasound Diagnostics (China); Wan Yi, E-mail: yiwan@163.com [The Fourth Military Medical University, Department of Health Statistics, Institute for Health Informatics (China); Duan Yunyou, E-mail: yunyouduan@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Ultrasound Diagnostics (China)

    2013-06-15

    Purpose. This study evaluates the influence of transcatheter arterial infusion with heated saline on hepatic arterial and portal venous blood flows to tumor and normal hepatic tissues in a rabbit VX2 tumor model. Methods. All animal experiments were approved by the institutional animal care and use committee. Twenty rabbits with VX2 liver tumors were divided into the following two groups: (a) the treated group (n = 10), which received a 60 mL transarterial injection of 60 Degree-Sign C saline via the hepatic artery; (b) the control group (n = 10), which received a 60 mL injection of 37 Degree-Sign C saline via the hepatic artery. Using ultrasonography, the blood flows in both the portal vein and hepatic artery were measured, and the changes in the hemodynamic indices were recorded before and immediately after the injection. The changes in the tumor and normal liver tissues of the two groups were histopathologically examined by hematoxylin and eosin staining after the injection. Results. After the transcatheter arterial heated infusion, there was a decrease in the hepatic arterial blood flow to the tumor tissue, a significant decrease in the hepatic artery mean velocity (P < 0.05), and a significant increase in the resistance index (P < 0.05). On hematoxylin and eosin staining, there were no obvious signs of tissue destruction in the normal liver tissue or the tumor tissue after heated perfusion, and coagulated blood plasma was observed in the cavities of intratumoral blood vessels in the treated group. Conclusions. The changes in tumor blood flow in the rabbit VX2 tumor model were presumably caused by microthrombi in the tumor vessels, and the portal vein likely mediated the heat loss in normal liver tissue during the transarterial heated infusion.

  2. Relationship of cerebral blood flow to aortic-to-pulmonary collateral/shunt flow in single ventricles

    Science.gov (United States)

    Fogel, Mark A; Li, Christine; Wilson, Felice; Pawlowski, Tom; Nicolson, Susan C; Montenegro, Lisa M; Berenstein, Laura Diaz; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S; Harris, Matthew A; Whitehead, Kevin K; Clancy, Robert; Elci, Okan; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J

    2016-01-01

    Objective Patients with single ventricle can develop aortic-to-pulmonary collaterals (APCs). Along with systemic-to-pulmonary artery shunts, these structures represent a direct pathway from systemic to pulmonary circulations, and may limit cerebral blood flow (CBF). This study investigated the relationship between CBF and APC flow on room air and in hypercarbia, which increases CBF in patients with single ventricle. Methods 106 consecutive patients with single ventricle underwent 118 cardiac magnetic resonance (CMR) scans in this cross-sectional study; 34 prior to bidirectional Glenn (BDG) (0.50±0.30 years old), 50 prior to Fontan (3.19±1.03 years old) and 34 3–9 months after Fontan (3.98±1.39 years old). Velocity mapping measured flows in the aorta, cavae and jugular veins. Analysis of variance (ANOVA) and multiple linear regression were used. Significance was p<0.05. Results A strong inverse correlation was noted between CBF and APC/shunt both on room air and with hypercarbia whether CBF was indexed to aortic flow or body surface area, independent of age, cardiopulmonary bypass time, Po2 and Pco2 (R=−0.67–−0.70 for all patients on room air, p<0.01 and R=−0.49–−0.90 in hypercarbia, p<0.01). Correlations were not different between surgical stages. CBF was lower, and APCs/shunt flow was higher prior to BDG than in other stages. Conclusions There is a strong inverse relationship between CBF and APC/shunt flow in patients with single ventricle throughout surgical reconstruction on room air and in hypercarbia independent of other factors. We speculate that APC/shunt flow may have a negative impact on cerebral development and neurodevelopmental outcome. Interventions on APC may modify CBF, holding out the prospect for improving neurodevelopmental trajectory. Trial Registration Number NCT02135081. PMID:26048877

  3. CHARACTERIZATION OF RENAL BLOOD FLOW REGULATION BASED ON WAVELET COEFFICIENTS

    DEFF Research Database (Denmark)

    Pavlov, A.N.; Pavlova, O.N.; Mosekilde, Erik

    2010-01-01

    The purpose of this study is to demonstrate the possibility of revealing new characteristic features of renal blood flow autoregulation in healthy and pathological states through the application of discrete wavelet transforms to experimental time series for normotensive and hypertensive rats....... A reduction in the variability of the wavelet coefficients in hypertension is observed at both the microscopic level of the blood flow in efferent arterioles of individual nephrons and at the macroscopic level of the blood pressure in the main arteries. The reduction is manifest in both of the main frequency...

  4. Effect of Isometric Hand Grip Exercises on Blood Flow and Placement of IV Catheters for Administration of Chemotherapy.

    Science.gov (United States)

    Ozkaraman, Ayse; Yesilbalkan, Öznur Usta

    2016-04-01

    Complications may occur in the subcutaneous or subdermal tissues during IV administration of chemotherapy related to blood flow and catheter placement. Daily isometric hand grip exercises were evaluated for their effect on blood flow in the vessels of the nondominant arm before placement of IV catheters and the success rate of IV catheter placement on the first attempt. The study focused on patients with non-Hodgkin lymphoma receiving the first and second cycles of chemotherapy. The intervention group performed daily isometric hand grip exercises before chemotherapy with peripheral catheter insertion. The control group performed routine activities only. Blood flow was measured by ultrasound in the brachial artery (BA) and brachial vein (BV) of the nondominant arm before the first (T1) and second (T2) cycles of chemotherapy. Blood flow slightly increased in the intervention group at T2 compared to T1. In the control group, blood flow decreased in the BA and did not change in the BV at T2 compared to T1. The success rate for first-attempt placement of a peripheral IV catheter was the same for the intervention and control groups.

  5. Abnormality in cerebellar blood flow in solo vertigo patients

    Energy Technology Data Exchange (ETDEWEB)

    Nagahori, Takeshi [Shakaihoken Takaoka Hospital, Toyama (Japan); Nishijima, Michiharu; Endo, Shunro; Takaku, Akira

    1997-03-01

    Little is known about the blood flow of the vertebrobasilar system as a cause of vertigo and dizziness. We used Xe-CT to study cerebellar blood flow in 53 patients who ranged in age from 35 to 85 years. The patients were divided into two groups. One of them was the vertigo group that comprised 28 patients with rotatory sensation, and the other, the non-vertigo group of 25 patients with a sensation other than rotation. At the stage of severe symptoms, there was decreased cerebellar blood flow in all patients of both, the vertigo and the non-vertigo groups, and a decrease in the bilateral cerebellar hemisphere was observed in five patients and in a unilateral hemisphere in three patients of the vertigo group. By comparison, in the non-vertigo group, unilateral decrease of cerebellar blood flow was observed in only one patient, and a bilateral decrease in five. At the stage of severe symptoms, the mean regional cerebellar blood flow was 40.5{+-}8.0 ml/100 g/min (n=16 sides) in the vertigo group and 45.3{+-}9.5 ml/100 g/min (n=12 sides) in the non-vertigo group. At the stage of moderate symptoms, blood flow image was normal in four of 14 vertigo patients and in seven of 12 non-vertigo patients. The mean regional blood flow was 47.8{+-}8.6 ml/100 g/min (n=28 sides) in the vertigo group and 47.1{+-}5.1 ml/100 g/min (n=24 sides) in the non-vertigo group. At the asymptomatic stage, a high proportion of normal blood flow images (nine of 16 vertigo patients and 10 of 10 non-vertigo patients) was observed. The mean regional cerebellar blood flow was 51.6{+-}10.7 ml/100 g/min (n=32 sides) in the vertigo group and 52.8{+-}8.5 ml/100 g/min (n=20 sides) in the non-vertigo group. This study demonstrates that a unilateral or bilateral decrease in blood flow of the vertebrobasilar system may cause vertigo and dizziness. It also shows that Xe-CT of the cerebellum may be a valuable examination modality for the diagnosis and treatment of vertigo and dizziness. (author)

  6. Abnormality in cerebellar blood flow in solo vertigo patients

    International Nuclear Information System (INIS)

    Nagahori, Takeshi; Nishijima, Michiharu; Endo, Shunro; Takaku, Akira

    1997-01-01

    Little is known about the blood flow of the vertebrobasilar system as a cause of vertigo and dizziness. We used Xe-CT to study cerebellar blood flow in 53 patients who ranged in age from 35 to 85 years. The patients were divided into two groups. One of them was the vertigo group that comprised 28 patients with rotatory sensation, and the other, the non-vertigo group of 25 patients with a sensation other than rotation. At the stage of severe symptoms, there was decreased cerebellar blood flow in all patients of both, the vertigo and the non-vertigo groups, and a decrease in the bilateral cerebellar hemisphere was observed in five patients and in a unilateral hemisphere in three patients of the vertigo group. By comparison, in the non-vertigo group, unilateral decrease of cerebellar blood flow was observed in only one patient, and a bilateral decrease in five. At the stage of severe symptoms, the mean regional cerebellar blood flow was 40.5±8.0 ml/100 g/min (n=16 sides) in the vertigo group and 45.3±9.5 ml/100 g/min (n=12 sides) in the non-vertigo group. At the stage of moderate symptoms, blood flow image was normal in four of 14 vertigo patients and in seven of 12 non-vertigo patients. The mean regional blood flow was 47.8±8.6 ml/100 g/min (n=28 sides) in the vertigo group and 47.1±5.1 ml/100 g/min (n=24 sides) in the non-vertigo group. At the asymptomatic stage, a high proportion of normal blood flow images (nine of 16 vertigo patients and 10 of 10 non-vertigo patients) was observed. The mean regional cerebellar blood flow was 51.6±10.7 ml/100 g/min (n=32 sides) in the vertigo group and 52.8±8.5 ml/100 g/min (n=20 sides) in the non-vertigo group. This study demonstrates that a unilateral or bilateral decrease in blood flow of the vertebrobasilar system may cause vertigo and dizziness. It also shows that Xe-CT of the cerebellum may be a valuable examination modality for the diagnosis and treatment of vertigo and dizziness. (author)

  7. Reversal in the Diameter of the Superior Ophthalmic Vein after an Epidural Blood Patch in a Case of Spontaneous Intracranial Hypotension

    International Nuclear Information System (INIS)

    Hsiao, Chen Yu; Tsai, Yuh Feng

    2011-01-01

    Spontaneous intracranial hypotension (SIH) is caused by single or multiple cerebrospinal fluid (CSF) leaks in the spine with the prototypical symptom of postural headache. One of the characteristic MRI features in SIH is intracranial venous engorgement. This report presents a case of SIH with engorgement of the bilateral superior ophthalmic veins (SOVs) which resume their normal diameters by the third day of successful epidural blood patches (EBPs). We define this phenomenon as the 'reversal of the SOV' sign.

  8. Quantification of complex blood flow using real-time in vivo vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per

    2010-01-01

    A quantitative method for distinguishing complex from non-complex flow patterns in ultrasound is presented. A new commercial BK Medical ultrasound scanner uses the Transverse Oscillation vector flow technique for visualising flow patterns in real-time. In vivo vector flow data of the blood flow...... patterns of the common carotid artery and the carotid bulb were obtained simultaneously as the basis for quantifying complex flow. The carotid bifurcation of two healthy volunteers were scanned. The presence of complex flow patterns from eight cardiac cycles were evaluated by three experts in medical...... for automatic detection of complex flow patterns....

  9. The effects of hypoxemia on myocardial blood flow during exercise.

    Science.gov (United States)

    Paridon, S M; Bricker, J T; Dreyer, W J; Reardon, M; Smith, E O; Porter, C B; Michael, L; Fisher, D J

    1989-03-01

    We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Regional cerebral blood flow in focal cortical epilepsy

    DEFF Research Database (Denmark)

    Hougaard, Kristina Dupont; Oikawa, T; Sveinsdottir, E

    1976-01-01

    Regional cerebral blood flow (rCBF) was studied in ten patients with focal cortical epilepsy. The blood flow was measured by the intra-arterial injection of xenon 133 (133Xe), and the isotope clearance was recorded by a multidetector scintillation camera with 254 detectors. Three patients were....... This finding accords with earlier studies. All nine patients studied in the interictal phase showed, either spontaneously or during activation by intermittent light, focal flow increases in areas presumed to comprise the epileptic focus. These interictal hyperemic foci probably reflect subictal neuronal...

  11. Viscoelastic capillary flow: the case of whole blood

    Directory of Open Access Journals (Sweden)

    David Rabaud

    2016-07-01

    Full Text Available The dynamics of spontaneous capillary flow of Newtonian fluids is well-known and can be predicted by the Lucas-Washburn-Rideal (LWR law. However a wide variety of viscoelastic fluids such as alginate, xanthan and blood, does not exhibit the same Newtonian behavior.In this work we consider the Herschel-Bulkley (HB rheological model and Navier-Stokes equation to derive a generic expression that predicts the capillary flow of non-Newtonian fluids. The Herschel-Bulkley rheological model encompasses a wide variety of fluids, including the Power-law fluids (also called Ostwald fluids, the Bingham fluids and the Newtonian fluids. It will be shown that the proposed equation reduces to the Lucas-Washburn-Rideal law for Newtonian fluids and to the Weissenberg-Rabinowitsch-Mooney (WRM law for power-law fluids. Although HB model cannot reduce to Casson’s law, which is often used to model whole blood rheology, HB model can fit the whole blood rheology with the same accuracy.Our generalized expression for the capillary flow of non-Newtonian fluid was used to accurately fit capillary flow of whole blood. The capillary filling of a cylindrical microchannel by whole blood was monitored. The blood first exhibited a Newtonian behavior, then after 7 cm low shear stress and rouleaux formation made LWR fails to fit the data: the blood could not be considered as Newtonian anymore. This non-Newtonian behavior was successfully fit by the proposed equation.

  12. Age and gender related differences in aortic blood flow

    DEFF Research Database (Denmark)

    Traberg, Marie Sand; Pedersen, Mads Møller; Hemmsen, Martin Christian

    2012-01-01

    The abdominal aorta (AA) is predisposed to development of abdominal aneurysms (AAA), a focal dilatation of the artery with fatal consequences if left untreated. The blood flow patterns in the AA is thought to play an important role in the development of AAA. The purpose of this work is to investi......The abdominal aorta (AA) is predisposed to development of abdominal aneurysms (AAA), a focal dilatation of the artery with fatal consequences if left untreated. The blood flow patterns in the AA is thought to play an important role in the development of AAA. The purpose of this work...... is to investigate the blood flow pat- terns within a group of healthy volunteers (4 females, 7 males) aged 23 to 76 years to identify changes and differences related to age and gender. The healthy volunteers were categorized by gender (male/female) and age (below/above 35 years). Subject-specific flow and geometry...... to elderly. Thus, changes in blood flow patterns in the AA related to age and gender is observed. Further investigations are needed to determine the relation between changes in blood flow patterns and AAA development....

  13. Prediction of blood pressure and blood flow in stenosed renal arteries using CFD

    Science.gov (United States)

    Jhunjhunwala, Pooja; Padole, P. M.; Thombre, S. B.; Sane, Atul

    2018-04-01

    In the present work an attempt is made to develop a diagnostive tool for renal artery stenosis (RAS) which is inexpensive and in-vitro. To analyse the effects of increase in the degree of severity of stenosis on hypertension and blood flow, haemodynamic parameters are studied by performing numerical simulations. A total of 16 stenosed models with varying degree of stenosis severity from 0-97.11% are assessed numerically. Blood is modelled as a shear-thinning, non-Newtonian fluid using the Carreau model. Computational Fluid Dynamics (CFD) analysis is carried out to compute the values of flow parameters like maximum velocity and maximum pressure attained by blood due to stenosis under pulsatile flow. These values are further used to compute the increase in blood pressure and decrease in available blood flow to kidney. The computed available blood flow and secondary hypertension for varying extent of stenosis are mapped by curve fitting technique using MATLAB and a mathematical model is developed. Based on these mathematical models, a quantification tool is developed for tentative prediction of probable availability of blood flow to the kidney and severity of stenosis if secondary hypertension is known.

  14. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...... pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons...

  15. Skeletal blood flow: implications for bone-scan interpretation

    International Nuclear Information System (INIS)

    Charkes, N.D.

    1980-01-01

    The dispersion of the skeleton throughout the body and its complex vascular anatomy require indirect methods for the measurement of skeletal blood flow. The results of one such method, compartmental analysis of skeletal tracer kinetics, are presented. The assumptions underlying the models were tested in animals and found to be in agreement with experimental observations. Based upon the models and the experimental results, inferences concerning bone-scan interpretation can be drawn: decreased cardiac output produces low-contrast (technically poor) scans; decreased skeletal flow produces photon-deficient lesions; increase of cardiac output or of generalized systemic blood flow is undetectable 1 to 2 h after dose; increased local skeletal blood flow results from disturbance of the bone microvasculature and can occur from neurologic (sympatholytic) disorders or in association with focal abnormalities that also incite the formation of reactive bone (e.g., metastasis, fracture, etc.). Mathematical solutions of tracer kinetic data thus become relevant to bone-scan interpretation

  16. Intrinsic regulation of blood flow in adipose tissue

    DEFF Research Database (Denmark)

    Henriksen, O; Nielsen, Steen Levin; Paaske, W

    1976-01-01

    Previous studies on intact human subcutaneous tissue have shown, that blood flow remains constant during minor changes in perfusion pressure. This so-called autoregulatory response has not been demonstrable in isolated preparations of adipose tissue. In the present study on isolated, denervated...... subcutaneous tissue in female rabbits only 2 of 12 expts. revealed an autoregulatory response during reduction in arterial perfusion pressure. Effluent blood flow from the tissue in the control state was 15.5 ml/100 g-min (S.D. 6.4, n = 12) corresponding to slight vasodilatation of the exposed tissue...... vasoconstriction with pronounced flow reduction. These two reactions may be important for local regulation of blood flow in subcutaneous tissue during orthostatic changes in arterial and venous pressure. It is concluded that the response in adipose tissue to changes in arterial pressure (autoregulation), venous...

  17. Supraorbital cutaneous blood flow rate during carotid endarterectomy

    DEFF Research Database (Denmark)

    Hove, Jens D; Rosenberg, Iben; Sejrsen, Per

    2006-01-01

    : The supraorbital cutaneous blood flow rate was measured by the application of heat to the skin and following the subsequent dissipation of the heat in seven patients undergoing carotid endarterectomy. At the same time, the oxygenation in the right and left frontal region was monitored by near-infrared spectroscopy......BACKGROUND: The supraorbital skin region is supplied by the supraorbital artery, which is a branch of the internal carotid artery. The supraorbital cutaneous blood flow rate may therefore be influenced by changes in the internal carotid artery flow during carotid endarterectomy. METHODS...... (NIRS). RESULTS: During cross-clamping of the carotid artery, the ipsilateral NIRS-determined frontal oxygenation tended to decrease [67 +/- 13% to 61 +/- 11% (P = 0.06); contralateral 68 +/- 11% to 66 +/- 8%] as did the supraorbital cutaneous blood flow rate from 56 +/- 23 to 44 +/- 7 ml 100 g(-1) min...

  18. Pulsatile blood flow, shear force, energy dissipation and Murray's Law

    Directory of Open Access Journals (Sweden)

    Bengtsson Hans-Uno

    2006-08-01

    Full Text Available Abstract Background Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow. Methods To determine the implications of the constant shear force hypothesis and to extend Murray's energy cost minimization to the pulsatile arterial system, a model of pulsatile flow in an elastic tube is analyzed. A new and exact solution for flow velocity, blood flow rate and shear force is derived. Results For medium and small arteries with pulsatile flow, Murray's energy minimization leads to Murray's Law. Furthermore, the hypothesis that the maximum shear force during the cycle of pulsatile flow is constant throughout the arterial system implies that Murray's Law is approximately true. The approximation is good for all but the largest vessels (aorta and its major branches of the arterial system. Conclusion A cellular mechanism that senses shear force at the inner wall of a blood vessel and triggers remodeling that increases the circumference of the wall when a shear force threshold is exceeded would result in the observed scaling of vessel radii described by Murray's Law.

  19. Partitioning of red blood cell aggregates in bifurcating microscale flows

    Science.gov (United States)

    Kaliviotis, E.; Sherwood, J. M.; Balabani, S.

    2017-03-01

    Microvascular flows are often considered to be free of red blood cell aggregates, however, recent studies have demonstrated that aggregates are present throughout the microvasculature, affecting cell distribution and blood perfusion. This work reports on the spatial distribution of red blood cell aggregates in a T-shaped bifurcation on the scale of a large microvessel. Non-aggregating and aggregating human red blood cell suspensions were studied for a range of flow splits in the daughter branches of the bifurcation. Aggregate sizes were determined using image processing. The mean aggregate size was marginally increased in the daughter branches for a range of flow rates, mainly due to the lower shear conditions and the close cell and aggregate proximity therein. A counterintuitive decrease in the mean aggregate size was apparent in the lower flow rate branches. This was attributed to the existence of regions depleted by aggregates of certain sizes in the parent branch, and to the change in the exact flow split location in the T-junction with flow ratio. The findings of the present investigation may have significant implications for microvascular flows and may help explain why the effects of physiological RBC aggregation are not deleterious in terms of in vivo vascular resistance.

  20. Portal venous blood flow while breath-holding after inspiration or expiration and during normal respiration in controls and cirrhotics

    International Nuclear Information System (INIS)

    Sugano, Shigeo; Yamamoto, Kunihiro; Sasao, Ken-ichiro; Watanabe, Manabu

    1999-01-01

    In this study, we used magnetic resonance (MR) imaging to measure portal blood flow in 12 healthy controls and 17 cirrhotics while they were breath-holding after inspiration and after expiration. We then compared the results with measurements made during normal respiration in the healthy controls and cirrhotics. Blood flow in the main portal vein under basal fasting conditions was quantitated using the cine phase-contrast MR velocity mapping method. Three measurements were made on one occasion, as follows: throughout the cardiac cycle during normal respiration, with the subject breath-holding after maximal inspiration, and with the subject breath-holding after maximal expiration. During normal respiration, portal blood flow was 1.3±0.2 l/min in controls vs 1.0±0.1 l/min in cirrhotics (P<0.0001); while subjects were breath-holding after inspiration, portal blood flow was 1.0±0.2 l/min in controls vs 0.9±0.1 l/min in cirrhotics; and while subjects were breath-holding after expiration, portal blood flow was 1.5±0.2 l/min in controls vs 1.1±0.2 l/min in cirrhotics (P<0.0001). The differences were primarily due to changes in flow velocity. When the magnitude of these hemodynamic changes in the three respiratory conditions was compared in controls and cirrhotics, analysis of variance (ANOVA) showed a significant difference (P<0.0001). In controls, portal blood flow decreased during maximal inspiration relative to flow during normal respiration (-24.6±8.3%). Changes in portal blood flow in controls were greater than in cirrhotics (-13.5±4.5%) (P<0.0001); however, the difference in blood flow increase associated with maximal expiration between the two groups (+11.8±9.4% vs +5.9±11.5%) was not significant. We found that the respiration-induced hemodynamic variation in portal blood flow was less in cirrhotics than in the healthy controls. Portal blood flow measurements made during normal respiration using MR imaging closely reflect nearly physiologic conditions

  1. Portal venous blood flow while breath-holding after inspiration or expiration and during normal respiration in controls and cirrhotics

    Energy Technology Data Exchange (ETDEWEB)

    Sugano, Shigeo; Yamamoto, Kunihiro; Sasao, Ken-ichiro; Watanabe, Manabu [Saiseikai Wakakusa Hospital, Yakohama (Japan)

    1999-07-01

    In this study, we used magnetic resonance (MR) imaging to measure portal blood flow in 12 healthy controls and 17 cirrhotics while they were breath-holding after inspiration and after expiration. We then compared the results with measurements made during normal respiration in the healthy controls and cirrhotics. Blood flow in the main portal vein under basal fasting conditions was quantitated using the cine phase-contrast MR velocity mapping method. Three measurements were made on one occasion, as follows: throughout the cardiac cycle during normal respiration, with the subject breath-holding after maximal inspiration, and with the subject breath-holding after maximal expiration. During normal respiration, portal blood flow was 1.3{+-}0.2 l/min in controls vs 1.0{+-}0.1 l/min in cirrhotics (P<0.0001); while subjects were breath-holding after inspiration, portal blood flow was 1.0{+-}0.2 l/min in controls vs 0.9{+-}0.1 l/min in cirrhotics; and while subjects were breath-holding after expiration, portal blood flow was 1.5{+-}0.2 l/min in controls vs 1.1{+-}0.2 l/min in cirrhotics (P<0.0001). The differences were primarily due to changes in flow velocity. When the magnitude of these hemodynamic changes in the three respiratory conditions was compared in controls and cirrhotics, analysis of variance (ANOVA) showed a significant difference (P<0.0001). In controls, portal blood flow decreased during maximal inspiration relative to flow during normal respiration (-24.6{+-}8.3%). Changes in portal blood flow in controls were greater than in cirrhotics (-13.5{+-}4.5%) (P<0.0001); however, the difference in blood flow increase associated with maximal expiration between the two groups (+11.8{+-}9.4% vs +5.9{+-}11.5%) was not significant. We found that the respiration-induced hemodynamic variation in portal blood flow was less in cirrhotics than in the healthy controls. Portal blood flow measurements made during normal respiration using MR imaging closely reflect nearly

  2. Cerebral blood flow tomography with xenon-133

    DEFF Research Database (Denmark)

    Lassen, N A

    1985-01-01

    computed tomograph (SPECT) is required. Two brain-dedicated SPECT systems designed for this purpose are mentioned, and the method is described with special reference to the limitations inherent in the soft energy of the 133Xe primary photons. CBF tomography can be used for a multitude of clinical...... of other tracers for CBF tomography using SPECT is summarized with emphasis on the 99mTc chelates that freely pass the intact blood-brain barrier. The highly sensitive brain-dedicated SPECT systems described are a prerequisite for achieving high resolution tomograms with such tracers....

  3. The effect of ventricular assist devices on cerebral blood flow and blood pressure fractality

    International Nuclear Information System (INIS)

    Bellapart, Judith; Fraser, John F; Chan, Gregory S H; Tzeng, Yu-Chieh; Ainslie, Philip N; Dunster, Kimble R; Barnett, Adrian G; Boots, Rob

    2011-01-01

    Biological signals often exhibit self-similar or fractal scaling characteristics which may reflect intrinsic adaptability to their underlying physiological system. This study analysed fractal dynamics of cerebral blood flow in patients supported with ventricular assist devices (VAD) to ascertain if sustained modifications of blood pressure waveform affect cerebral blood flow fractality. Simultaneous recordings of arterial blood pressure and cerebral blood flow velocity using transcranial Doppler were obtained from five cardiogenic shock patients supported by VAD, five matched control patients and five healthy subjects. Computation of a fractal scaling exponent (α) at the low-frequency time scale by detrended fluctuation analysis showed that cerebral blood flow velocity exhibited 1/f fractal scaling in both patient groups (α = 0.95 ± 0.09 and 0.97 ± 0.12, respectively) as well as in the healthy subjects (α = 0.86 ± 0.07). In contrast, fluctuation in blood pressure was similar to non-fractal white noise in both patient groups (α = 0.53 ± 0.11 and 0.52 ± 0.09, respectively) but exhibited 1/f scaling in the healthy subjects (α = 0.87 ± 0.04, P < 0.05 compared with the patient groups). The preservation of fractality in cerebral blood flow of VAD patients suggests that normal cardiac pulsation and central perfusion pressure changes are not the integral sources of cerebral blood flow fractality and that intrinsic vascular properties such as cerebral autoregulation may be involved. However, there is a clear difference in the fractal scaling properties of arterial blood pressure between the cardiogenic shock patients and the healthy subjects

  4. Tissues viability and blood flow sensing based on a new nanophotonics method

    Science.gov (United States)

    Yariv, Inbar; Haddad, Menashe; Duadi, Hamootal; Motiei, Menachem; Fixler, Dror

    2018-02-01

    Extracting optical parameters of turbid medium (e.g. tissue) by light reflectance signals is of great interest and has many applications in the medical world, life science, material analysis and biomedical optics. The reemitted light from an irradiated tissue is affected by the light's interaction with the tissue components and contains the information about the tissue structure and physiological state. In this research we present a novel noninvasive nanophotonics technique, i.e., iterative multi-plane optical property extraction (IMOPE) based on reflectance measurements. The reflectance based IMOPE was applied for tissue viability examination, detection of gold nanorods (GNRs) within the blood circulation as well as blood flow detection using the GNRs presence within the blood vessels. The basics of the IMOPE combine a simple experimental setup for recording light intensity images with an iterative Gerchberg-Saxton (G-S) algorithm for reconstructing the reflected light phase and computing its standard deviation (STD). Changes in tissue composition affect its optical properties which results in changes in the light phase that can be measured by its STD. This work presents reflectance based IMOPE tissue viability examination, producing a decrease in the computed STD for older tissues, as well as investigating their organic material absorption capability. Finally, differentiation of the femoral vein from adjacent tissues using GNRs and the detection of their presence within blood circulation and tissues are also presented with high sensitivity (better than computed tomography) to low quantities of GNRs (<3 mg).

  5. Cine-CT measurement of cortical renal blood flow

    International Nuclear Information System (INIS)

    Jaschke, W.R.; Gould, R.G.; Cogan, M.G.; Sievers, R.; Lipton, M.J.

    1987-01-01

    A modified indicator-dilution technique using radiographic contrast material and a cine-CT scanner was used to measure blood flow in the renal cortex of dogs. To validate this technique, CT measurements were correlated with simultaneous measurements of flow determined by radioactive microspheres. Measurements were taken during euvolemic conditions and after hemorrhage. Thirty-nine measurements were compared, covering a flow range from 1 to 7 ml min-1 g-1, and a good correlation was found between the cine-CT and microsphere results (r = 0.93; p less than 0.001). Additionally, cine-CT measurements were made of the mean transit time (MTT) of contrast material through the renal cortex, and the reciprocal of these MTT values was also well correlated to microsphere determined flow (r = 0.94; p less than 0.001). Thus, cine-CT appears to be a promising new technique for measuring renal blood flow

  6. Predicting bifurcation angle effect on blood flow in the microvasculature.

    Science.gov (United States)

    Yang, Jiho; Pak, Y Eugene; Lee, Tae-Rin

    2016-11-01

    Since blood viscosity is a basic parameter for understanding hemodynamics in human physiology, great amount of research has been done in order to accurately predict this highly non-Newtonian flow property. However, previous works lacked in consideration of hemodynamic changes induced by heterogeneous vessel networks. In this paper, the effect of bifurcation on hemodynamics in a microvasculature is quantitatively predicted. The flow resistance in a single bifurcation microvessel was calculated by combining a new simple mathematical model with 3-dimensional flow simulation for varying bifurcation angles under physiological flow conditions. Interestingly, the results indicate that flow resistance induced by vessel bifurcation holds a constant value of approximately 0.44 over the whole single bifurcation model below diameter of 60μm regardless of geometric parameters including bifurcation angle. Flow solutions computed from this new model showed substantial decrement in flow velocity relative to other mathematical models, which do not include vessel bifurcation effects, while pressure remained the same. Furthermore, when applying the bifurcation angle effect to the entire microvascular network, the simulation results gave better agreements with recent in vivo experimental measurements. This finding suggests a new paradigm in microvascular blood flow properties, that vessel bifurcation itself, regardless of its angle, holds considerable influence on blood viscosity, and this phenomenon will help to develop new predictive tools in microvascular research. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. MR measurement of coronary arterial blood flow velocity. Evaluation of age, stenosis and drugs as factors affecting coronary blood flow

    International Nuclear Information System (INIS)

    Taoka, Yoshiaki; Harada, Masafumi; Nishitani, Hiromu; Yukinaka, Michiko; Nomura, Masahiro

    1998-01-01

    Coronary arterial blood flow velocity was measured using MRI. Two types of phase contrast methods were used for the measurements, one of which exhibited good resolving power whereas the other provided more distinct images acquired while the subject patients held their breath. Before measuring coronary arterial blood flow velocity, accuracy of the two phase contrast methods was evaluated using a phantom. The results obtained with both methods largely agreed with the values obtained using the phantom. Using both methods, the patterns of coronary arterial blood flow over one cardiac cycle were essentially identical. A peak was noted in late systole or in early diastole in the right coronary artery, whereas in the left coronary artery, a peak was noted somewhat later in diastole. In healthy volunteers, no significant difference in the maximal flow velocity in the coronary arteries was found from one age group to another. Among patients with coronary arterial stenosis, coronary arterial blood flow velocity central to the area of stenosis was lower than that observed in the healthy volunteers. Coronary arterial blood flow velocity was observed to decrease after administration of isosorbide dinitrate and increased following administration of nifedipine. (author)

  8. The effect of altering pulmonary blood flow on pulmonary gas exchange in the turtle Trachemys (Pseudemys) scripta.

    Science.gov (United States)

    Hopkins, S R; Wang, T; Hicks, J W

    1996-10-01

    In resting reptiles, the PO2 of pulmonary venous return (PLAO2; left atrial blood) may be 20 mmHg (1 mmHg = 0.1333 kPa) lower than the PO2 of gas in the lung. This level of PO2 is considerably higher than that observed in resting mammals and birds and results from ventilation-perfusion (V/Q) heterogeneity, pulmonary diffusion limitation and intrapulmonary shunting. However, the relative contribution of each of these factors is unknown. Many reptiles, particularly chelonians, exhibit an intermittent ventilation pattern where pulmonary blood flow (QL) increases during the ventilatory periods and, therefore, we hypothesized that V/Q matching would improve with increasing QL. We applied the multiple inert gas elimination technique in anaesthetized turtles at 22 degrees C. Turtles were continuously ventilated at a rate of 140 ml kg-1 min-1, equivalent to the rate of ventilation within a ventilatory period. Trace amounts of six inert gases were infused through the jugular vein. Blood samples from the pulmonary artery and the left atrium and mixed expired gases were collected for analysis. QL was reduced by a factor of six (low flow) using a vascular occluder placed around the common pulmonary artery or increased by a factor of two (high flow) through bolus injection of adrenaline. V/Q heterogeneity was significantly reduced with increasing pulmonary blood flow (P means +/- S.E.M.) and PLAO2 increased significantly (P < 0.05) from 88 +/- 17 mmHg (low flow) to 120 +/- 14 mmHg (high flow). There was evidence of pulmonary diffusion limitation under all conditions, which was unchanged with increasing blood flow. These findings suggest that increased pulmonary blood flow during a ventilatory period results in both temporal and spatial matching of ventilation and perfusion, without altering pulmonary diffusion limitation.

  9. Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko

    1986-11-01

    Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis.

  10. Sex differences of human cortical blood flow and energy metabolism.

    Science.gov (United States)

    Aanerud, Joel; Borghammer, Per; Rodell, Anders; Jónsdottir, Kristjana Y; Gjedde, Albert

    2017-07-01

    Brain energy metabolism is held to reflect energy demanding processes in neuropil related to the density and activity of synapses. There is recent evidence that men have higher density of synapses in temporal cortex than women. One consequence of these differences would be different rates of cortical energy turnover and blood flow in men and women. To test the hypotheses that rates of oxygen consumption (CMRO 2 ) and cerebral blood flow are higher in men than in women in regions of cerebral cortex, and that the differences persist with aging, we used positron emission tomography to determine cerebral blood flow and cerebral metabolic rate of oxygen as functions of age in healthy volunteers of both sexes. Cerebral metabolic rate of oxygen did not change with age for either sex and there were no differences of mean values of cerebral metabolic rate of oxygen between men and women in cerebral cortex. Women had significant decreases of cerebral blood flow as function of age in frontal and parietal lobes. Young women had significantly higher cerebral blood flow than men in frontal and temporal lobes, but these differences had disappeared at age 65. The absent sex difference of cerebral energy turnover suggests that the known differences of synaptic density between the sexes are counteracted by opposite differences of individual synaptic activity.

  11. Radionuclide study on hepatic blood flow in Schistosomiasis Japonica

    International Nuclear Information System (INIS)

    Okada, Junichi; Uchiyama, Guio; Hayakawa, Kazushige; Hayashi, Sanshin; Araki, Tsutomu; Arai, Takao; Iuchi, Masahiko.

    1986-01-01

    Schistosomiasis Japonica is a regional disease found in elderly people who were living in once-endemic areas in Japan. Yamanashi was one of these areas until 1970, since when no newly infected patients were reported. The disease is characteristic of developing irreversible interstitial fibrosis of the liver, where parasites migrate and lay eggs. Portal hypertension, esophageal varices and hepatocellular carcinomas are the common features of the results. In order to estimate patient's hepatic blood flow, radionuclide angiography of the liver with the use of 10 - 15 millicuries of Tc-99m phytate were performed prior to the conventional multiview imaging. Twenty-two patients with schistosomiasis and twelve adults without evidence of liver disease were studied. A time-activity curve of the right lobe of the liver was generated by a computer, and the ratio of arterial blood flow to portal blood flow was calculated. As a result, a good correlation was found between the arterial to portal blood flow ratio and the grade of hepatic fibrosis verified by laparoscopic biopsy. The development of esophageal varices were likely to correlate well with the blood flow ratio rather than scores on the conventional static liver and spleen scintigram. The study was useful for evaluating patient's clinical stages and prognosis. (author)

  12. Impact of extracorporeal blood flow rate on blood pressure, pulse rate and cardiac output during haemodialysis

    DEFF Research Database (Denmark)

    Schytz, Philip Andreas; Mace, Maria Lerche; Soja, Anne Merete Boas

    2015-01-01

    BACKGROUND: If blood pressure (BP) falls during haemodialysis (HD) [intradialytic hypotension (IDH)] a common clinical practice is to reduce the extracorporeal blood flow rate (EBFR). Consequently the efficacy of the HD (Kt/V) is reduced. However, only very limited knowledge on the effect...

  13. Dynamics of blood flow: twenty years of achievement

    International Nuclear Information System (INIS)

    Rosendorff, C.

    1988-01-01

    The physiology of blood circulation has evolved from the descriptive phenomenology of William Harvey's time to an interdisciplinary science, involving elements of fluid dynamics, vessel wall mechanics, electrophysiology, cell biology, biochemistry and molecular biology. Most of these new developments have occured during the lifetime of the South African Medical Research Council. Highlights of the research undertaken by the Council regarding circulatory physiology are given. In the 1960s the use of xenon-133 to study the flow of blood to the brain resulted in the first systematic description of cerebral blood flow and its control by sympathetic nerves. During the 1970s this technique was refined and the use of radioactive microspheres for the measurement of tissue blood flow was developed. Research concerning the control of blood vessels in the kidney was also carried out, and this showed that the sympathetic nerves control renal blood flow by releasing a local hormone called renin. The renal release of renin was later recognised as being important in the control of blood pressure. Another development was the discovery that vascular sensitivity to noradrenaline was increased in certain types of liver diseases. An analysis of the blood of patients with obstructive jaundice showed that the substance responsible for this noradrenaline effect was a combination of cholesterol and lipo-protein. This led to the theory that excessive cholesterol in the blood may be dangerous. In the late 1970s a shift in research emphasis to coronary artery physiology occurred and the 1980s saw research move into the area of cell biology

  14. Quantification of cerebral blood flow via Duplex sonography

    International Nuclear Information System (INIS)

    Vogl, G.; Pohl, P.; Willeit, J.; Aichner, F.

    1987-01-01

    An attempt was made to measure quantitatively the total cerebral blood flow by means of Duplex sonography. In a group of healthy young subjects a median value for total cerebral blood flow was obtained amounting to 469 ml/min ± 30%, repeat measurements yielded a maximum deviation of ± 11%. In three patients the values obtained after severe apoplectic insult due to occlusion of the internal carotid artery were definitely below the value of the group of healthy subjects, whereas the value for the total blood flow was in the upper range of normal values in a patient with occlusion of the a. cerebri media. Comparative measurements of the regional cerebral blood flow with xenon 13 yielded in those patients with occlusion of the internal carotid artery a markedly reduced mean flow and in the patient with occlusion of the a. cerebri media a less markedly reduced mean flow. Regionally reduced perfusion was seen in all the four patients in the range of the clinically and computer tomographically well-known ischaemia zone. Thanks to the simplicity of this sonographic examination method it could be a useful decision parameter in determining the indication for a reconstruction of the carotid artery, especially in asymptotic patients. (orig.) [de

  15. Measurement of regional hepatic blood flow by scintiphotosplenoportography

    Energy Technology Data Exchange (ETDEWEB)

    Kashiwagi, T; Kimura, K; Kamada, T; Abe, H [Osaka Univ. (Japan). Dept. of Radiology and Nuclear Medicine

    1978-08-01

    A new technique for estimating regional hepatic blood flow using the inert gas washout technique and scintillation camera following injection of /sup 133/Xe into the spleen is presented. This technique is easily, rapidly and repeatedly performed and permits the measurement of nutrient hepatic tissue blood flow. Measurement of regional hepatic blood flow in right and/or left lobes was performed in 28 patients. In all but one patient the right lobar flow value was equal to or greater than the left one. The right lobar flow was 86.20 +- 12.83 ml/100 gm/min in 3 patients without liver disease, 75.12 +- 14.54 ml/100 gm/min in 12 with chronic hepatitis and 51.24 +- 17.13 ml/100 gm/min in 11 with liver cirrhosis. This result suggests that hepatic tissue blood flow is significantly decreased in patients with liver cirrhosis. Scintillation camera images of initial xenon distribution in combination with monitor of washout curves over the liver also provide more information on the presence of extra- and intrahepatic shunts. Therefore, this technique appears to be clinically useful in evaluation of hemodynamic phenomena associated with liver diseases.

  16. Influences of Hydraulic Fracturing on Fluid Flow and Mineralization at the Vein-Type Tungsten Deposits in Southern China

    Directory of Open Access Journals (Sweden)

    Xiangchong Liu

    2017-01-01

    Full Text Available Wolframite is the main ore mineral at the vein-type tungsten deposits in the Nanling Range, which is a world-class tungsten province. It is disputed how wolframite is precipitated at these deposits and no one has yet studied the links of the mechanical processes to fluid flow and mineralization. Finite element-based numerical experiments are used to investigate the influences of a hydraulic fracturing process on fluid flow and solubility of CO2 and quartz. The fluids are aqueous NaCl solutions and fluid pressure is the only variable controlling solubility of CO2 and quartz in the numerical experiments. Significant fluctuations of fluid pressure and high-velocity hydrothermal pulse are found once rock is fractured by high-pressure fluids. The fluid pressure drop induced by hydraulic fracturing could cause a 9% decrease of quartz solubility. This amount of quartz deposition may not cause a significant decrease in rock permeability. The fluid pressure decrease after hydraulic fracturing also reduces solubility of CO2 by 36% and increases pH. Because an increase in pH would cause a major decrease in solubility of tungsten, the fluid pressure drop accompanying a hydraulic fracturing process facilitates wolframite precipitation. Our numerical experiments provide insight into the mechanisms precipitating wolframite at the tungsten deposits in the Nanling Range as well as other metals whose solubility is strongly dependent on pH.

  17. Improved instrumentation for blood flow velocity measurements in the microcirculation of small animals

    International Nuclear Information System (INIS)

    Mesquita, Jayme Alves Jr. de; Bouskela, Eliete; Wajnberg, Eliane; Lopes de Melo, Pedro

    2007-01-01

    Microcirculation is the generic name of vessels with internal diameter less than 100 μm of the circulatory system, whose main functions are tissue nutrition and oxygen supply. In microcirculatory studies, it is important to know the amount of oxyhemoglobin present in the blood and how fast it is moving. The present work describes improvements introduced in a classical hardware-based instrument that has usually been used to monitor blood flow velocity in the microcirculation of small animals. It consists of a virtual instrument that can be easily incorporated into existing hardware-based systems, contributing to reduce operator related biases and allowing digital processing and storage. The design and calibration of the modified instrument are described as well as in vitro and in vivo results obtained with electrical models and small animals, respectively. Results obtained in in vivo studies showed that this new system is able to detect a small reduction in blood flow velocity comparing arteries and arterioles (p<0.002) and a further reduction in capillaries (p<0.0001). A significant increase in velocity comparing capillaries and venules (p<0.001) and venules and veins (p<0.001) was also observed. These results are in close agreement with biophysical principles. Moreover, the improvements introduced in the device allowed us to clearly observe changes in blood flow introduced by a pharmacological intervention, suggesting that the system has enough temporal resolution to track these microcirculatory events. These results were also in close conformity to physiology, confirming the high scientific potential of the modified system and indicating that this instrument can also be useful for pharmacological evaluations

  18. Regulation of the skeletal muscle blood flow in humans

    DEFF Research Database (Denmark)

    Mortensen, Stefan; Saltin, Bengt

    2014-01-01

    In humans, skeletal muscle blood flow is regulated by an interaction between several locally formed vasodilators including nitric oxide (NO) and prostaglandins. In plasma, ATP is a potent vasodilator that stimulates the formation of NO and prostaglandins and very importantly can offset local...... concentration does not increase during exercise. In the skeletal muscle interstitium, there is a marked increase in the concentration of ATP and adenosine and this increase is tightly coupled to the increase in blood flow. The sources of interstitial ATP and adenosine are thought to be skeletal muscle cells...... hyperaemia whereas the role of ATP remains uncertain due to lack of specific purinergic receptor blockers for human use. The purpose of this review is to address the interaction between vasodilator systems and to discuss the multiple proposed roles of ATP in human skeletal muscle blood flow regulation...

  19. A dynamic model of renal blood flow autoregulation

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H; Marsh, D J

    1994-01-01

    To test whether a mathematical model combining dynamic models of the tubuloglomerular feedback (TGF) mechanism and the myogenic mechanism was sufficient to explain dynamic autoregulation of renal blood flow, we compared model simulations with experimental data. To assess the dynamic characteristics...... of renal autoregulation, a broad band perturbation of the arterial pressure was employed in both the simulations and the experiments. Renal blood flow and tubular pressure were used as response variables in the comparison. To better approximate the situation in vivo where a large number of individual...... data, which shows a unimodal curve for the admittance phase. The ability of the model to reproduce the experimental data supports the hypothesis that dynamic autoregulation of renal blood flow is due to the combined action of TGF and the myogenic response....

  20. Noninvasive measurement of blood flow and extraction fraction

    Energy Technology Data Exchange (ETDEWEB)

    Peters, A.M.; Gunasekera, R.D.; Henderson, B.L.; Brown, J.; Lavender, J.P.; De Souza, M.; Ash, J.M.; Gilday, D.L.

    1987-10-01

    We describe the theory of a technique for the noninvasive measurement of organ blood flow which is based on the principle of fractionation of cardiac output and is applicable with any recirculating gamma emitting tracer. The technique effectively determines the count rate that would be recorded over the organ if the tracer behaved like radiolabelled microspheres and was completely trapped in the organ's vascular bed on first pass. After correction for organ depth, the estimated first pass activity plateau, expressed as a fraction of the injected dose is equal to the organ's fraction of the cardiac output (CO). By extending the theory, organ extraction fraction of extractable tracers or mean transit time of nonextractable tracers can be measured. The technique was applied to the measurement of renal blood flow in the native and transplanted kidney, splenic blood flow, the extraction fraction of DTPA by the kidney and of sulphur colloid by the spleen.

  1. Renal transplantant blood flow in patients with acute tubular necrosis

    Energy Technology Data Exchange (ETDEWEB)

    Huic, D; Crnkovic, S; Bubic-Filipi, L J; Grosev, D; Dodig, P; Porapat, M; Puretic, Z [Univ. Hospital Rebro, Zagreb (Croatia)

    1997-09-01

    The aim of this study was to investigate the quantity of renal transport blood flow in patients affected by acute tubular necrosis (ATN). During the four years period two hundred and thirty-three studies were performed using {sup 99m}Tc pertechnetate and {sup 131}I - OIH. Renal blood flow was calculated from the first-pass time activity curves generated over the kidney and aorta and expressed as a percentage of cardiac output (RBF/CO). Renal transplant blood flow is clearly diminished in ATN, similar as in acute rejection, and significantly related to the graft function, what means that RBF/CO value could potentially serve as a prognostic factor in the graft function recovery from ATN.

  2. Noninvasive measurement of blood flow and extraction fraction

    International Nuclear Information System (INIS)

    Peters, A.M.; Gunasekera, R.D.; Henderson, B.L.; Brown, J.; Lavender, J.P.; De Souza, M.; Ash, J.M.; Gilday, D.L.

    1987-01-01

    We describe the theory of a technique for the noninvasive measurement of organ blood flow which is based on the principle of fractionation of cardiac output and is applicable with any recirculating gamma emitting tracer. The technique effectively determines the count rate that would be recorded over the organ if the tracer behaved like radiolabelled microspheres and was completely trapped in the organ's vascular bed on first pass. After correction for organ depth, the estimated first pass activity plateau, expressed as a fraction of the injected dose is equal to the organ's fraction of the cardiac output (CO). By extending the theory, organ extraction fraction of extractable tracers or mean transit time of nonextractable tracers can be measured. The technique was applied to the measurement of renal blood flow in the native and transplanted kidney, splenic blood flow, the extraction fraction of DTPA by the kidney and of sulphur colloid by the spleen. (author)

  3. Reduced blood flow to contracting skeletal muscle in ageing humans

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Hellsten, Ylva

    2016-01-01

    The ability to sustain a given absolute submaximal workload declines with advancing age likely due to a lower level of blood flow and O2 delivery to the exercising muscles. Given that physical inactivity mimics many of the physiological changes associated with ageing, separating the physiological...... consequences of ageing and physical inactivity can be challenging; yet, observations from cross-sectional and longitudinal studies on the effects of physical activity have provided some insight. Physical activity has the potential to offset the age-related decline in blood flow to contracting skeletal muscle...... the O2 demand of the active skeletal muscle of aged individuals during conditions where systemic blood flow is not limited by cardiac output seems to a large extent to be related to the level of physical activity. This article is protected by copyright. All rights reserved....

  4. A numerical study of blood flow using mixture theory.

    Science.gov (United States)

    Wu, Wei-Tao; Aubry, Nadine; Massoudi, Mehrdad; Kim, Jeongho; Antaki, James F

    2014-03-01

    In this paper, we consider the two dimensional flow of blood in a rectangular microfluidic channel. We use Mixture Theory to treat this problem as a two-component system: One component is the red blood cells (RBCs) modeled as a generalized Reiner-Rivlin type fluid, which considers the effects of volume fraction (hematocrit) and influence of shear rate upon viscosity. The other component, plasma, is assumed to behave as a linear viscous fluid. A CFD solver based on OpenFOAM ® was developed and employed to simulate a specific problem, namely blood flow in a two dimensional micro-channel, is studied. Finally to better understand this two-component flow system and the effects of the different parameters, the equations are made dimensionless and a parametric study is performed.

  5. Sex differences of human cortical blood flow and energy metabolism

    DEFF Research Database (Denmark)

    Aanerud, Joel; Borghammer, Per; Rodell, Anders

    2017-01-01

    cerebral blood flow and cerebral metabolic rate of oxygen as functions of age in healthy volunteers of both sexes. Cerebral metabolic rate of oxygen did not change with age for either sex and there were no differences of mean values of cerebral metabolic rate of oxygen between men and women in cerebral...... cortex. Women had significant decreases of cerebral blood flow as function of age in frontal and parietal lobes. Young women had significantly higher cerebral blood flow than men in frontal and temporal lobes, but these differences had disappeared at age 65. The absent sex difference of cerebral energy...... turnover suggests that the known differences of synaptic density between the sexes are counteracted by opposite differences of individual synaptic activity....

  6. Vascular reactivity of mesenteric arteries and veins to endothelin-1 in a murine model of high blood pressure.

    Science.gov (United States)

    Pérez-Rivera, Alex A; Fink, Gregory D; Galligan, James J

    2005-06-01

    We characterized vascular reactivity to endothelin-1 (ET-1) in mesenteric vessels from DOCA-salt hypertensive and SHAM control mice and assessed the effect that endothelial-derived vasodilators have on ET-1-induced vasoconstriction. Changes in the diameter of unpressurized small mesenteric arteries and veins (100- to 300-microm outside diameter) were measured in vitro using computer-assisted video microscopy. Veins were more sensitive than arteries to the contractile effects of ET-1. There was a decrease in arterial maximal responses (E(max)) compared to veins, this effect was larger in DOCA-salt arteries. The selective ET(B) receptor agonist, sarafotoxin 6c (S6c), contracted DOCA-salt and SHAM veins but did not contract arteries. The ET(B) receptor antagonist, BQ-788 (100 nM), but not the ET(A) receptor antagonist, BQ-610 (100 nM), blocked S6c responses. BQ-610 partially inhibited responses to ET-1 in mesenteric veins from DOCA-salt and SHAM mice while BQ-788 did not affect responses to ET-1. Co-administration of both antagonists inhibited responses to ET-1 to a greater extent than BQ-610 alone suggesting a possible functional interaction between ET(A) and ET(B) receptors. Responses to ET-1 in mesenteric arteries were completely inhibited by BQ-610 while BQ-788 did not affect arterial responses. Nitric oxide synthase inhibition potentiated ET-1 responses in veins from SHAM but not DOCA-salt mice. There was a prominent role for ET-mediated nitric oxide release in DOCA-salt but not SHAM arteries. In summary, these studies showed a differential regulation of ET-1 contractile mechanisms between murine mesenteric arteries and veins.

  7. Coronary blood flow during cardiopulmonary resuscitation in swine

    International Nuclear Information System (INIS)

    Bellamy, R.F.; DeGuzman, L.R.; Pedersen, D.C.

    1984-01-01

    Recent papers have raised doubt as to the magnitude of coronary blood flow during closed-chest cardiopulmonary resuscitation. We will describe experiments that concern the methods of coronary flow measurement during cardiopulmonary resuscitation. Nine anesthetized swine were instrumented to allow simultaneous measurements of coronary blood flow by both electromagnetic cuff flow probes and by the radiomicrosphere technique. Cardiac arrest was caused by electrical fibrillation and closed-chest massage was performed by a Thumper (Dixie Medical Inc., Houston). The chest was compressed transversely at a rate of 66 strokes/min. Compression occupied one-half of the massage cycle. Three different Thumper piston strokes were studied: 1.5, 2, and 2.5 inches. Mean aortic pressure and total systemic blood flow measured by the radiomicrosphere technique increased as Thumper piston stroke was lengthened (mean +/- SD): 1.5 inch stroke, 23 +/- 4 mm Hg, 525 +/- 195 ml/min; 2 inch stroke, 33 +/- 5 mm Hg, 692 +/- 202 ml/min; 2.5 inch stroke, 40 +/- 6 mm Hg, 817 +/- 321 ml/min. Both methods of coronary flow measurement (electromagnetic [EMF] and radiomicrosphere [RMS]) gave similar results in technically successful preparations (data expressed as percent prearrest flow mean +/- 1 SD): 1.5 inch stroke, EMF 12 +/- 5%, RMS 16 +/- 5%; 2 inch stroke, EMF 30 +/- 6%, RMS 26 +/- 11%; 2.5 inch stroke, EMF 50 +/- 12%, RMS 40 +/- 20%. The phasic coronary flow signal during closed-chest compression indicated that all perfusion occurred during the relaxation phase of the massage cycle. We concluded that coronary blood flow is demonstrable during closed-chest massage, but that the magnitude is unlikely to be more than a fraction of normal

  8. Radiolabeled microsphere measurements of alveolar bone blood flow in dogs

    International Nuclear Information System (INIS)

    Kaplan, M.L.; Jeffcoat, M.K.; Goldhaber, P.

    1978-01-01

    Radiolabeled microspheres were injected into the left cardiac ventricle in healthy adult dogs to quantify blood in maxillary and mandibular alveolar bone. Heart rate, arterial blood pressure and pulse contour were monitored throughout each experiment. Blood flow in maxillary alveolar bone was more than 30 % greater (p<.001) than in mandibular alveolar bone. Alveolar bone blood flow (mean +- S.D.) measured as ml/min per gram was 0.12 +- .02 in the maxilla compared to 0.09 +- .02 in the mandible. The cardiovascular parameters monitored were constant immediately prior to the injection of microspheres and remained unchanged during and following injection. It is possible that radiolabeled microspheres can be used to quantify the circulatory changes in alveolar bone during the development of destructive periodontal disease in dogs. (author)

  9. Effect of pregnancy on regional cerebral blood flow

    International Nuclear Information System (INIS)

    Nagamachi, Shigeki; Hoshi, Hiroaki; Jinnouchi, Seishi; Ohnishi, Takashi; Futami, Shigemi; Watanabe, Katsushi; Ikeda, Tomoaki; Mori, Norimasa

    1993-01-01

    Regional cerebral blood flow (r-CBF) of 10 pregnant women were quantified by 133 Xe SPECT study with inhalation method before and after artificial abortion. During pregnancy, value of r-CBF in each region except occipital lobe was significantly higher than that of the post abortion. Arterial blood gas was analyzed after SPECT procedure. P co2 concentration increased significantly after artificial abortion. Although its mechanism is unknown, our preliminary work demonstrates that r-CBF increased by pregnancy. (author)

  10. Relationship of cerebral blood flow to aortic-to-pulmonary collateral/shunt flow in single ventricles.

    Science.gov (United States)

    Fogel, Mark A; Li, Christine; Wilson, Felice; Pawlowski, Tom; Nicolson, Susan C; Montenegro, Lisa M; Diaz Berenstein, Laura; Spray, Thomas L; Gaynor, J William; Fuller, Stephanie; Keller, Marc S; Harris, Matthew A; Whitehead, Kevin K; Clancy, Robert; Elci, Okan; Bethel, Jim; Vossough, Arastoo; Licht, Daniel J

    2015-08-01

    Patients with single ventricle can develop aortic-to-pulmonary collaterals (APCs). Along with systemic-to-pulmonary artery shunts, these structures represent a direct pathway from systemic to pulmonary circulations, and may limit cerebral blood flow (CBF). This study investigated the relationship between CBF and APC flow on room air and in hypercarbia, which increases CBF in patients with single ventricle. 106 consecutive patients with single ventricle underwent 118 cardiac magnetic resonance (CMR) scans in this cross-sectional study; 34 prior to bidirectional Glenn (BDG) (0.50±0.30 years old), 50 prior to Fontan (3.19±1.03 years old) and 34 3-9 months after Fontan (3.98±1.39 years old). Velocity mapping measured flows in the aorta, cavae and jugular veins. Analysis of variance (ANOVA) and multiple linear regression were used. Significance was pflow or body surface area, independent of age, cardiopulmonary bypass time, Po2 and Pco2 (R=-0.67--0.70 for all patients on room air, pflow was higher prior to BDG than in other stages. There is a strong inverse relationship between CBF and APC/shunt flow in patients with single ventricle throughout surgical reconstruction on room air and in hypercarbia independent of other factors. We speculate that APC/shunt flow may have a negative impact on cerebral development and neurodevelopmental outcome. Interventions on APC may modify CBF, holding out the prospect for improving neurodevelopmental trajectory. NCT02135081. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  11. Renal blood flow and oxygenation drive nephron progenitor differentiation.

    Science.gov (United States)

    Rymer, Christopher; Paredes, Jose; Halt, Kimmo; Schaefer, Caitlin; Wiersch, John; Zhang, Guangfeng; Potoka, Douglas; Vainio, Seppo; Gittes, George K; Bates, Carlton M; Sims-Lucas, Sunder

    2014-08-01

    During kidney development, the vasculature develops via both angiogenesis (branching from major vessels) and vasculogenesis (de novo vessel formation). The formation and perfusion of renal blood vessels are vastly understudied. In the present study, we investigated the regulatory role of renal blood flow and O2 concentration on nephron progenitor differentiation during ontogeny. To elucidate the presence of blood flow, ultrasound-guided intracardiac microinjection was performed, and FITC-tagged tomato lectin was perfused through the embryo. Kidneys were costained for the vasculature, ureteric epithelium, nephron progenitors, and nephron structures. We also analyzed nephron differentiation in normoxia compared with hypoxia. At embryonic day 13.5 (E13.5), the major vascular branches were perfused; however, smaller-caliber peripheral vessels remained unperfused. By E15.5, peripheral vessels started to be perfused as well as glomeruli. While the interior kidney vessels were perfused, the peripheral vessels (nephrogenic zone) remained unperfused. Directly adjacent and internal to the nephrogenic zone, we found differentiated nephron structures surrounded and infiltrated by perfused vessels. Furthermore, we determined that at low O2 concentration, little nephron progenitor differentiation was observed; at higher O2 concentrations, more differentiation of the nephron progenitors was induced. The formation of the developing renal vessels occurs before the onset of blood flow. Furthermore, renal blood flow and oxygenation are critical for nephron progenitor differentiation. Copyright © 2014 the American Physiological Society.

  12. Relationship between insulin resistance and tissue blood flow in preeclampsia.

    Science.gov (United States)

    Anim-Nyame, Nick; Gamble, John; Sooranna, Suren R; Johnson, Mark R; Steer, Philip J

    2015-05-01

    Preeclampsia is characterized by generalized endothelial dysfunction and impaired maternal tissue perfusion, and insulin resistance is a prominent feature of this disease. The aim of this study was to test the hypothesis that insulin resistance in preeclampsia is related to the reduced resting tissue blood flow. We used venous occlusion plethysmography to compare the resting calf muscle blood flow (measured as QaU) in 20 nulliparous women with preeclampsia and 20 normal pregnant controls matched for maternal age, gestational age, parity and BMI during the third trimester. Fasting blood samples were obtained to measure the plasma concentrations of insulin and glucose, and to calculate the fasting insulin resistance index (FIRI), a measure of insulin resistance in both groups of women. Calf blood flow was significantly reduced in the preeclampsia group (1.93 ± 0.86 QaU), compared with normal pregnant controls (3.94 ± 1.1 QaU, P insulin concentrations and Insulin Resistance Index were significantly higher in preeclampsia compared with normal pregnancy (P insulin concentrations (r = -0.57, P = 0.008) and FIRI (r = -0.59, P = 0.006) in preeclampsia, but not in normal pregnancy. These findings support our hypothesis and raise the possibility that reduced tissue blood flow may a play a role in the increased insulin resistance seen in preeclampsia.

  13. Follicle vascularity coordinates corpus luteum blood flow and progesterone production.

    Science.gov (United States)

    de Tarso, S G S; Gastal, G D A; Bashir, S T; Gastal, M O; Apgar, G A; Gastal, E L

    2017-03-01

    Colour Doppler ultrasonography was used to compare the ability of preovulatory follicle (POF) blood flow and its dimensions to predict the size, blood flow and progesterone production capability of the subsequent corpus luteum (CL). Cows (n=30) were submitted to a synchronisation protocol. Follicles ≥7mm were measured and follicular wall blood flow evaluated every 12h for approximately 3.5 days until ovulation. After ovulation, cows were scanned daily for 8 days and similar parameters were evaluated for the CL. Blood samples were collected and plasma progesterone concentrations quantified. All parameters were positively correlated. Correlation values ranged from 0.26 to 0.74 on data normalised to ovulation and from 0.31 to 0.74 on data normalised to maximum values. Correlations between calculated ratios of both POF and CL in data normalised to ovulation and to maximum values ranged from moderate (0.57) to strong (0.87). Significant (Pprogesterone concentrations of the resultant CL. These findings indicate that follicle vascularity coordinates CL blood flow and progesterone production in synchronised beef cows.

  14. Uteroplacental blood flow during alkalosis in the sheep

    International Nuclear Information System (INIS)

    Buss, D.D.; Bisgard, G.E.; Rawlings, C.A.; Rankin, J.H.G.

    1975-01-01

    Uteroplacental blood flow was measured by the radioactive-microsphere technique in eight near-term pregnant ewes during a normal control period and during maternal metabolic alkalosis. All measurements were made on awake, unanesthetized animals. Alkalosis, defined for this study as an arterial pH of 7.60 or greater, was produced by the oral administration of sodium bicarbonate, 3 g/kg body wt. The rise in pH thus produced was unaccompanied by significant changes in systemic arterial blood pressure and cardiac output, while maternal arterial P/sub CO 2 / rose slightly from control levels. Cotyledonary blood flow declined from a control value of 1.177 ml/min to 1.025 ml/min during alkalosis. This decline of 13 percent in cotyledonary blood flow is significant (P less than 0.02). Blood flow to the remaining uterine tissue, or noncotyledonary uterus, did not change with alkalosis, being maintained at approximately 195 ml/min. It is concluded that maternal alkalosis, unaccompanied by major changes in P /sub CO 2 / and systemic arterial pressure, causes a small increase in the resistance of the uteroplacental circulation

  15. Inner ocular blood flow responses to an acute decrease in blood pressure in resting humans

    International Nuclear Information System (INIS)

    Ikemura, Tsukasa; Kashima, Hideaki; Yamaguchi, Yuji; Miyaji, Akane; Hayashi, Naoyuki

    2015-01-01

    Whether inner ocular vessels have an autoregulatory response to acute fluctuations in blood pressure is unclear. We tried to examine the validity of acute hypotension elicited by thigh-cuff release as to assess the dynamic autoregulation in the ocular circulation. Blood flow velocity in the superior nasal and inferior temporal retinal arterioles, and in the retinal and choroidal vasculature were measured with the aid of laser speckle flowgraphy before and immediately after an acute decrease in blood pressure in 20 healthy subjects. Acute hypotension was induced by a rapid release of bilateral thigh occlusion cuffs that had been inflated to 220 mmHg for 2 min. The ratio of the relative change in retinal and choroidal blood flow velocity to the relative change in mean arterial blood pressure (MAP) was calculated. Immediately after cuff release, the MAP and blood flows in the all ocular target vessels decreased significantly from the baseline values obtained before thigh-cuff release. The ratio of the relative change in inner ocular blood flow velocity to that in the MAP exceeded 1% / %mmHg. An explicit dynamic autoregulation in inner ocular vessels cannot be demonstrated in response to an acute hypotension induced by the thigh-cuff release technique. (paper)

  16. A feasability study of color flow doppler vectorization for automated blood flow monitoring.

    Science.gov (United States)

    Schorer, R; Badoual, A; Bastide, B; Vandebrouck, A; Licker, M; Sage, D

    2017-12-01

    An ongoing issue in vascular medicine is the measure of the blood flow. Catheterization remains the gold standard measurement method, although non-invasive techniques are an area of intense research. We hereby present a computational method for real-time measurement of the blood flow from color flow Doppler data, with a focus on simplicity and monitoring instead of diagnostics. We then analyze the performance of a proof-of-principle software implementation. We imagined a geometrical model geared towards blood flow computation from a color flow Doppler signal, and we developed a software implementation requiring only a standard diagnostic ultrasound device. Detection performance was evaluated by computing flow and its determinants (flow speed, vessel area, and ultrasound beam angle of incidence) on purposely designed synthetic and phantom-based arterial flow simulations. Flow was appropriately detected in all cases. Errors on synthetic images ranged from nonexistent to substantial depending on experimental conditions. Mean errors on measurements from our phantom flow simulation ranged from 1.2 to 40.2% for angle estimation, and from 3.2 to 25.3% for real-time flow estimation. This study is a proof of concept showing that accurate measurement can be done from automated color flow Doppler signal extraction, providing the industry the opportunity for further optimization using raw ultrasound data.

  17. 1-D blood flow modelling in a running human body.

    Science.gov (United States)

    Szabó, Viktor; Halász, Gábor

    2017-07-01

    In this paper an attempt was made to simulate blood flow in a mobile human arterial network, specifically, in a running human subject. In order to simulate the effect of motion, a previously published immobile 1-D model was modified by including an inertial force term into the momentum equation. To calculate inertial force, gait analysis was performed at different levels of speed. Our results show that motion has a significant effect on the amplitudes of the blood pressure and flow rate but the average values are not effected significantly.

  18. Blood flow in curved pipe with radiative heat transfer

    International Nuclear Information System (INIS)

    Ogulu, A.; Bestman, A.R.

    1992-03-01

    Blood flow in a curved pipe such as the aorta is modelled in this study. The aorta is modelled as a curved pipe of slowly varying cross-section. Asymptotic series expansions about a small parameter δ, which is a measure of the curvature ratio is employed to obtain the velocity and temperature distributions. The study simulates the effect of radio-frequency heating, for instance during physiotherapy, on the flow of blood in the cardiovascular system assuming an external constant pressure gradient; and our results agree very well with results obtained by Pedley. (author). 9 refs, 2 figs

  19. Disparity in regional cerebral blood flow during electrically induced seizure

    DEFF Research Database (Denmark)

    Sestoft, D; Meden, P; Hemmingsen, R

    1993-01-01

    This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized on electroencepha......This is a presentation of 2 cases in which the intraictal regional cerebral blood flow distribution was measured with the 99mTc-HMPAO single photon emission computerized tomography technique during an electrically induced seizure. Although the seizure was verified as generalized...... electroencephalography-verified generalized seizures....

  20. Oscillations and Multiple Equilibria in Microvascular Blood Flow.

    Science.gov (United States)

    Karst, Nathaniel J; Storey, Brian D; Geddes, John B

    2015-07-01

    We investigate the existence of oscillatory dynamics and multiple steady-state flow rates in a network with a simple topology and in vivo microvascular blood flow constitutive laws. Unlike many previous analytic studies, we employ the most biologically relevant models of the physical properties of whole blood. Through a combination of analytic and numeric techniques, we predict in a series of two-parameter bifurcation diagrams a range of dynamical behaviors, including multiple equilibria flow configurations, simple oscillations in volumetric flow rate, and multiple coexistent limit cycles at physically realizable parameters. We show that complexity in network topology is not necessary for complex behaviors to arise and that nonlinear rheology, in particular the plasma skimming effect, is sufficient to support oscillatory dynamics similar to those observed in vivo.

  1. Heterogeneity of cerebral blood flow: a fractal approach

    International Nuclear Information System (INIS)

    Kuikka, J.T.; Hartikainen, P.

    2000-01-01

    Aim: We demonstrate the heterogeneity of regional cerebral blood flow using a fractal approach and single-photon emission computed tomography (SPECT). Method: Tc-99m-labelled ethylcysteine dimer was injected intravenously in 10 healthy controls and in 10 patients with dementia of frontal lobe type. The head was imaged with a gamma camera and transaxial, sagittal and coronal slices were reconstructed. Two hundred fifty-six symmetrical regions of interest (ROIs) were drawn onto each hemisphere of functioning brain matter. Fractal analysis was used to examine the spatial heterogeneity of blood flow as a function of the number of ROIs. Results: Relative dispersion (=coefficient of variation of the regional flows) was fractal-like in healthy subjects and could be characterized by a fractal dimension of 1.17±0.05 (mean±SD) for the left hemisphere and 1.15±0.04 for the right hemisphere, respectively. The fractal dimension of 1.0 reflects completely homogeneous blood flow and 1.5 indicates a random blood flow distribution. Patients with dementia of frontal lobe type had a significantly lower fractal dimension of 1.04±0.03 than in healthy controls. (orig.) [de

  2. Effect of warming and flow rate conditions of blood warmers on red blood cell integrity.

    Science.gov (United States)

    Poder, T G; Pruneau, D; Dorval, J; Thibault, L; Fisette, J-F; Bédard, S K; Jacques, A; Beauregard, P

    2016-11-01

    Fluid warmers are routinely used to reduce the risk of hypothermia and cardiac complications associated with the infusion of cold blood products. However, warming blood products could generate haemolysis. This study was undertaken to compare the impact of temperature of blood warmers on the per cent haemolysis of packed red blood cells (RBCs) heated at different flow rates as well as non-flow conditions. Infusion warmers used were calibrated at 41·5°C ± 0·5°C and 37·5°C ± 0·5°C. Cold RBC units stored at 4°C in AS-3 (n = 30), aged 30-39 days old, were divided into half units before being allocated under two different scenarios (i.e. infusion pump or syringe). Blood warmers were effective to warm cold RBCs to 37·5°C or 41·5°C when used in conjunction with an infusion pump at flow rate up to 600 ml/h. However, when the warmed blood was held in a syringe for various periods of time, such as may occur in neonatal transfusions, the final temperature was below the expected requirements with measurement as low as 33·1°C. Increasing the flow with an infusion pump increased haemolysis in RBCs from 0·2% to up to 2·1% at a flow rate of 600 ml/h regardless of the warming device used (P < 0·05). No relevant increase of haemolysis was observed using a syringe. The use of a blood warmer adjusted to 41·5°C is probably the best choice for reducing the risk of hypothermia for the patient without generating haemolysis. However, we should be cautious with the use of an infusion pump for RBC transfusion, particularly at high flow rates. © 2016 International Society of Blood Transfusion.

  3. Regional cerebral blood flow measurement using a scintillation camera

    International Nuclear Information System (INIS)

    Heiss, W.D.

    1979-01-01

    A scintillation camera connected to auxillary equipment with off-line data processing or connected to an on-line dedicated computer system permits measurement of hemispheric and regional cerebral blood flow. Reliable flow values are obtained from regions limited in size by spatial resolution and the count rates achieved. Flow measurements obtained with the camera are able to resolve inhomogeneities of cerebral circulation in normal subjects. In a variety of clinical conditions, the localization, severity and extent of flow alterations are shown. Results of flow measurements in individual cases elucidate the pathogenesis of neurologic deficits, quantify the damage to the brain, indicate therapeutic measures of potential value and permit an estimation of the further clinical course. With restricted spatial resolution, flow measurements after intravenous 133 Xe injection are also feasible

  4. Comparison between mechanical properties of human saphenous vein and umbilical vein

    Directory of Open Access Journals (Sweden)

    Hamedani Borhan

    2012-08-01

    Full Text Available Abstract Background As a main cause of mortality in developed countries, Coronary Artery Disease (CAD is known as silent killer with a considerable cost to be dedicated for its treatment. Coronary Artery Bypass Graft (CABG is a common remedy for CAD for which different blood vessels are used as a detour. There is a lack of knowledge about mechanical properties of human blood vessels used for CABG, and while these properties have a great impact on long-term patency of a CABG. Thus, studying these properties, especially those of human umbilical veins which have not been considered yet, looks utterly necessary. Methods Umbilical vein, as well as human Saphenous vein, are respectively obtained after cesarean and CABG. First, histological tests were performed to investigate different fiber contents of the samples. Having prepared samples carefully, force-displacement results of samples were rendered to real stress–strain measurements and then a fourth-order polynomial was used to prove the non-linear behavior of these two vessels. Results Results were analyzed in two directions, i.e. circumferentially and longitudinally, which then were compared with each other. The comparison between stiffness and elasticity of these veins showed that Saphenous vein’s stiffness is much higher than that of umbilical vein and also, it is less stretchable. Furthermore, for both vessels, longitudinal stiffness was higher than that of circumferential and in stark contrast, stretch ratio in circumferential direction came much higher than longitudinal orientation. Conclusion Blood pressure is very high in the region of aorta, so there should be a stiff blood vessel in this area and previous investigations showed that stiffer vessels would have a better influence on the flow of bypass. To this end, the current study has made an attempt to compare these two blood vessels’ stiffness, finding that Saphenous vein is stiffer than umbilical vein which is somehow as stiff as

  5. Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

    DEFF Research Database (Denmark)

    Sindrup, J H; Kastrup, J; Christensen, H

    1991-01-01

    Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage uni.......0001). The synchronism of the nocturnal subcutaneous hyperemia and the decrease in systemic mean arterial blood pressure point to a common, possibly central nervous or humoral, eliciting mechanism.......Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit...

  6. Esophageal blood flow in the cat. Normal distribution and effects of acid perfusion

    International Nuclear Information System (INIS)

    Hollwarth, M.E.; Smith, M.; Kvietys, P.R.; Granger, D.N.

    1986-01-01

    The radioactive microsphere technique was used to estimate blood flow to different regions of the esophagus and to adjacent regions of the stomach before and after perfusion of the esophagus with hydrochloric acid (pH 1.5) for 5 min. Under resting conditions total blood flow, as well as blood flow to the mucosal-submucosal layer and the muscular layer, to both sphincters was significantly higher than to the esophageal body. Blood flow to the adjacent regions of the stomach was significantly higher than esophageal blood flow. Acid perfusion resulted in a large increase in total blood flow in both sphincters and the lower esophageal body. Gastric blood flow was not altered by acid perfusion. The esophageal hyperemia resulted primarily from an increase in blood flow to the muscular layer; mucosal-submucosal blood flow was increased only in the lower esophageal sphincter. The present study indicates that short periods (5 min) of gastroesophageal reflux may increase esophageal blood flow

  7. Recovery of testicular blood flow following ligation of testicular vessels

    International Nuclear Information System (INIS)

    Pascual, J.A.; Villanueva-Meyer, J.; Salido, E.; Ehrlich, R.M.; Mena, I.; Rajfer, J.

    1989-01-01

    To determine whether initial ligation of the testicular vessels of the high undescended testis followed by a delayed secondary orchiopexy is a viable alternative to the classical Fowler-Stephens procedure, a series of preliminary experiments were conducted in the rat in which testicular blood flow was measured by the 133-xenon washout technique before, and 1 hour and 30 days after ligation of the vessels. In addition, testicular histology, and testis and sex-accessory tissue weights were measured in 6 control, 6 sham operated and 6 testicular vessel ligated rats 54 days after vessel ligation. The data demonstrate that ligation and division of the testicular blood vessels produce an 80 per cent decrease in testicular blood flow 1 hour after ligation of the vessels. However, 30 days later testis blood flow returns to the control and pre-treatment value. There were no significant changes in testis or sex-accessory tissue weights 54 days after vessel ligation. Histologically, 4 of the surgically operated testes demonstrated necrosis of less than 25 per cent of the seminiferous tubules while 1 testis demonstrated more than 75 per cent necrosis. The rest of the tubules in all 6 testes demonstrated normal spermatogenesis. From this study we conclude that initial testicular vessel ligation produces an immediate decrease in testicular blood flow but with time the collateral vessels are able to compensate and return the testis blood flow to its normal pre-treatment value. These preliminary observations lend support for the concept that initial ligation of the testicular vessels followed by a delayed secondary orchiopexy in patients with a high undescended testis may be a possible alternative to the classical Fowler-Stephens approach

  8. [Preclinical diagnostics and correction of the disturbed renal blood flow in the children presenting with diabetic nephropathy].

    Science.gov (United States)

    Aver'ianov, A P; Tkacheva, E N; Bolotova, N V; Filina, N Iu; Ivanova, Iu V; Nikolaeva, N V; Tikhonova, L A

    2011-01-01

    The present study included 86 children aged between 7 and 17 years with type 1 diabetes mellitus from 1 to 15 years in duration. In all the patients, renal blood flow was investigated with the use of ultrasonic dopplerography. The results of the study suggest disturbances of intrarenal hemodynamics that manifested themselves as enhanced resistance of renal arteries from periphery to the centre in the patients at the hyperfiltration stage of diabetic nephropathy (DN) in conjunction with the reduced velocity of blood flow in inter-lobular and segmental arteries. In contrast, the patients at the microalbuminuric stage of diabetic nephropathy exhibited increased resistance and reduced velocity of blood flow in the main renal veins. In 35 patients presenting with diabetic nephropathy, hemodynamic correction was achieved by the application of the traveling pulsed magnetic field (TP-MF) to the renal region using an AMO-ATOS-E apparatus (Russia). This treatment resulted in normalization of the characteristics of renal blood flow. It is concluded that TPMF has good prospects for the use as a component of the combined treatment of diabetic nephropathy.

  9. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Waahlin, Anders

    2012-07-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  10. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    International Nuclear Information System (INIS)

    Waahlin, Anders

    2012-01-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  11. Phase contrast MRI assessment of pedal blood flow

    International Nuclear Information System (INIS)

    Debatin, J.F.; Dalman, R.; Herfkens, R.J.; Harris, E.J.; Pelc, N.J.

    1995-01-01

    This study attempts to evaluate the reliability of cine phase contrast (PC) flow measurements in the assessment of normal pedal blood flow and quantitation of revascularisation-induced flow changes in patients with end-stage peripheral vascular occlusive disease (PVOD). Oblique axial cine-PC acquisitions were obtained on a 1.5 T MRI system at the level of the talotibial joints in 8 normal subjects on four separate occasions. Subsequently 8 patients with end-stage PVOD were examined before and after surgical revascularisation (bilateral, n = 2; unilateral, n = 6). Measured flow in the trifurcation vessels was highly variable among normal subjects. Total pedal flow ranged from 32 to 183 ml/min (mean 91 ml/min) and was significantly different between the subjects evaluated (P < 0.0001). Measurements in the same subject over time were considerably less variable (P < 0.005). Normal arterial flow patterns were consistently triphasic; those in patients with PVOD were either mono- or biphasic. Pedal flow measured by cine-PC in patients was reduced compared with normal subjects (mean 38.3 ml/min). Flow was slower in symptomatic limbs (26.7 ml/min) compared with asymptomatic ones (48.9 ml/min). Flow increases in revascularised limbs (mean 315%) were significantly different from those observed in non-affected limbs (P < 0.005). The ability to quantitate pedal blood flow and subsequent revascularisation-induced flow increases appears promising for the identification of optimal treatment options and monitoring of treatment results. (orig.)

  12. Blood flow analysis with considering nanofluid effects in vertical channel

    Science.gov (United States)

    Noreen, S.; Rashidi, M. M.; Qasim, M.

    2017-06-01

    Manipulation of heat convection of copper particles in blood has been considered peristaltically. Two-phase flow model is used in a channel with insulating walls. Flow analysis has been approved by assuming small Reynold number and infinite length of wave. Coupled equations are solved. Numerical solution are computed for the pressure gradient, axial velocity function and temperature. Influence of attention-grabbing parameters on flow entities has been analyzed. This study can be considered as mathematical representation to the vibrance of physiological systems/tissues/organs provided with medicine.

  13. Vasopressin-induced changes in splanchnic blood flow and hepatic and portal venous pressures in liver resection.

    Science.gov (United States)

    Bown, L Sand; Ricksten, S-E; Houltz, E; Einarsson, H; Söndergaard, S; Rizell, M; Lundin, S

    2016-05-01

    To minimize blood loss during hepatic surgery, various methods are used to reduce pressure and flow within the hepato-splanchnic circulation. In this study, the effect of low- to moderate doses of vasopressin, a potent splanchnic vasoconstrictor, on changes in portal and hepatic venous pressures and splanchnic and hepato-splanchnic blood flows were assessed in elective liver resection surgery. Twelve patients were studied. Cardiac output (CO), stroke volume (SV), mean arterial (MAP), central venous (CVP), portal venous (PVP) and hepatic venous pressures (HVP) were measured, intraoperatively, at baseline and during vasopressin infusion at two infusion rates (2.4 and 4.8 U/h). From arterial and venous blood gases, the portal (splanchnic) and hepato-splanchnic blood flow changes were calculated, using Fick's equation. CO, SV, MAP and CVP increased slightly, but significantly, while systemic vascular resistance and heart rate remained unchanged at the highest infusion rate of vasopressin. PVP was not affected by vasopressin, while HVP increased slightly. Vasopressin infusion at 2.4 and 4.8 U/h reduced portal blood flow (-26% and -37%, respectively) and to a lesser extent hepato-splanchnic blood flow (-9% and -14%, respectively). The arterial-portal vein lactate gradient was not significantly affected by vasopressin. Postoperative serum creatinine was not affected by vasopressin. Short-term low to moderate infusion rates of vasopressin induced a splanchnic vasoconstriction without metabolic signs of splanchnic hypoperfusion or subsequent renal impairment. Vasopressin caused a centralization of blood volume and increased cardiac output. Vasopressin does not lower portal or hepatic venous pressures in this clinical setting. © 2016 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  14. Phenotypic heterogeneity in the endothelium of the human vortex vein system.

    Science.gov (United States)

    Yu, Paula K; Tan, Priscilla E Z; Cringle, Stephen J; McAllister, Ian L; Yu, Dao-Yi

    2013-10-01

    The vortex vein system is the drainage pathway for the choroidal circulation and serves an important function in the effective drainage of the exceptionally high blood flow from the choroidal circulation. As there are only 4-6 vortex veins, a large volume of blood must be drained from many choroidal veins into each individual vortex vein. The vortex vein system must also cope with passing through tissues of different rigidity and significant pressure gradient as it transverses from the intrao-cular to the extra-ocular compartments. However, little is known about how the vortex vein system works under such complex situations in both physiological and pathological condition. Endothelial cells play a vital role in other vascular systems, but they have not been studied in detail in the vortex vein system. The purpose of this study is to characterise the intracellular structures and morphology in both the intra-and extra-ocular regions of the human vortex vein system. We hypothesise the presence of endothelial phenotypic heterogeneity through the vortex vein system. The inferior temporal vortex vein system from human donor eyes were obtained and studied histologically using confocal microscopy. The f-actin cytoskeleton and nuclei were labelled using Alexa Fluor conjugated Phalloidin and YO-PRO-1. Eight regions of the vortex vein system were examined with the venous endothelium studied in detail with quantitative data obtained for endothelial cell and nuclei size and shape. Significant endothelial phenotypic heterogeneity was found throughout the vortex vein system with the most obvious differences observed between the ampulla and its downstream regions. Variation in the distribution pattern of smooth muscle cells, in particular the absence of smooth muscle cells around the ampulla, was noted. Our results suggest the presence of significantly different haemodynamic forces in different regions of the vortex vein system and indicate that the vortex vein system may play

  15. Heterogeneity of brain blood flow and permeability during acute hypertension

    International Nuclear Information System (INIS)

    Baumbach, G.L.; Heistad, D.D.

    1985-01-01

    The purpose of this study was to examine regional autoregulation of blood flow in the brain during acute hypertension. In anesthetized cats severe hypertension increased blood flow more in cerebrum (159%) and cerebellum (106%) than brain stem (58%). In contrast to the heterogeneous autoregulatory response, hypocapnia produced uniform vasoconstriction in the brain. The authors also compared vasodilatation during severe hypertension with vasodilatation during hypercapnia. During hypercapnia, blood flow increased as much in brain stem, as in cerebrum and cerebellum. Thus, regional differences in autoregulation appear to be specific for autoregulatory stimulus and are not secondary to nonspecific differences in vasoconstrictor or vasodilator capacity. To determine whether the blood-brain barrier is more susceptible to hypertensive disruption in regions with less effective autoregulation, permeability of the barrier was quantitated with 125 I-albumin. Severe hypertension produced disruption of the barrier in cerebrum but not in brain stem. Thus, there are parallel differences in effectiveness of autoregulation and susceptibility to disruption of the blood-brain barrier in different regions of the brain

  16. Dynamics of renal blood flow autoregulation in rats

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H; Wagner, A J; Marsh, D J

    1991-01-01

    Two separate components could be resolved in tests of the dynamic autoregulation of renal blood flow. The slow component corresponds to the frequency at which spontaneous proximal tubular pressure oscillations are found, and are most likely due to the operation of the TGF. The high frequency...

  17. Simple technique for measuring relative renal blood flow

    International Nuclear Information System (INIS)

    Shames, D.M.; Korobkin, M.

    1976-01-01

    To determine whether externally monitored early renal uptake of 131 I-hippurate is proportional to renal blood flow, the renal uptake of 131 -hippurate at 1 to 2 min after injection was compared with the renal accumulation of radioactive carbonized microspheres in dogs. A renal artery catheter equipped with a balloon was used to decrease renal blood flow unilaterally. One minute after the intravenous injection of 100 μCi of 131 I-hippurate, about 1 μCi of either 85 Sr- or 95 Nb-labeled carbon microspheres was injected into the left ventricle. Radioactivity was measured over both kidneys. The total radioactivity within each kidney region of interest was corrected for background and integrated over the 1 to 2 min interval after injection. Thirteen measurements of relative renal blood flow were made for seven dogs. The dogs were then killed and both kidneys were excised and counted for the radioactivity of the microspheres. The 1 to 2-min relative renal uptake of 131 I-hippurate correlated well with relative microsphere uptake, suggesting that relative renal blood flow can be simply determined from the external measurements of renal uptake of 131 I-hippurate

  18. Subcortical aphasia and cerebral blood flow using SPECT

    International Nuclear Information System (INIS)

    Celsis, P.; Puel, M.; Demonet, J.P.; Bonafe, A.; Cardebat, D.; Viallard, G.; Pujol, T.; Marc-Vergnes, J.P.; Rascol, A.

    1985-01-01

    Possible cerebral blood flow (CBF) alteration in subcortical aphasia was investigated by single-photon emission tomography (SPECT). The results confirm the capsulo-striatal lesions and also point to the high rate of ipsilateral thalamic and cortical dysfunction. (author). 8 refs.; 1 fig.; 1 tab

  19. Splanchnic blood flow and hepatic glucose production in exercising humans

    DEFF Research Database (Denmark)

    Bergeron, R; Kjaer, M; Simonsen, L

    2001-01-01

    The study examined the implication of the renin-angiotensin system (RAS) in regulation of splanchnic blood flow and glucose production in exercising humans. Subjects cycled for 40 min at 50% maximal O(2) consumption (VO(2 max)) followed by 30 min at 70% VO(2 max) either with [angiotensin-converti......The study examined the implication of the renin-angiotensin system (RAS) in regulation of splanchnic blood flow and glucose production in exercising humans. Subjects cycled for 40 min at 50% maximal O(2) consumption (VO(2 max)) followed by 30 min at 70% VO(2 max) either with [angiotensin......-converting enzyme (ACE) blockade] or without (control) administration of the ACE inhibitor enalapril (10 mg iv). Splanchnic blood flow was estimated by indocyanine green, and splanchnic substrate exchange was determined by the arteriohepatic venous difference. Exercise led to an approximately 20-fold increase (P ...-blockade group vs. the control group, hormones, metabolites, VO(2), and RER followed the same pattern of changes in ACE-blockade and control groups during exercise. Splanchnic blood flow (at rest: 1.67 +/- 0.12, ACE blockade; 1.59 +/- 0.18 l/min, control) decreased during moderate exercise (0.78 +/- 0.07, ACE...

  20. Regional cerebral blood flow in primary degenerative dementia

    International Nuclear Information System (INIS)

    Kawakatsu, Shinobu; Totsuka, Shiro; Shinohara, Masao; Koyama, Hideki; Sagawa, Katsuo; Morinobu, Shigeru; Oiji, Arata; Komatani, Akio

    1991-01-01

    Regional cerebral blood flow (rCBF) was examined, using SPECT by Xe-133 inhalation, in patients with primary degenerative dementia who were subgrouped according to predominant symptoms with respect to amnesia, apraxia, agnosia, aphasia, and personality changes. Also the effect of sex and age at dementia onset on the rCBF patterns was assessed. (author). 26 refs.; 1 fig.; 7 tabs

  1. Velocity estimation using synthetic aperture imaging [blood flow

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Jensen, Jørgen Arendt

    2001-01-01

    Presented an approach for synthetic aperture blood flow ultrasound imaging. Estimates with a low bias and standard deviation can be obtained with as few as eight emissions. The performance of the new estimator is verified using both simulations and measurements. The results demonstrate that a fully...

  2. Nocturnal foot blood flow in patients with arterial insufficiency

    DEFF Research Database (Denmark)

    Jelnes, Rolf; Tønnesen, K H

    1984-01-01

    Twenty-four hour continuous recording of xenon (133Xe) wash-out from the forefoot was performed on patients with normal circulations (n = 10) and on patients with different degrees of arterial insufficiency (n = 36). During day hours the calculated subcutaneous blood flow in the forefoot was on a...

  3. Neurophysiological Basis of Cerebral Blood Flow Control: An ...

    African Journals Online (AJOL)

    The book describes the current understanding of cerebral blood flow ... metaoolism of the central nervous system. The brain ... in stroke it is a deficiency of the book that the clinical correlates are .... Review of Nutrition and Dietetics. Edited by ...

  4. Endoscopic retrograde cholangiopancreatography causes reduced myocardial blood flow

    DEFF Research Database (Denmark)

    Christensen, M; Hendel, H W; Rasmussen, V

    2002-01-01

    BACKGROUND AND STUDY AIMS: Previous studies have shown that up to 50% of healthy patients may develop ST-segment changes during upper gastrointestinal endoscopy. The aim of the study was to evaluate myocardial blood flow in patients during endoscopic retrograde cholangiopancreatography (ERCP...

  5. Single-photon emission tomography and cerebral blood flow

    International Nuclear Information System (INIS)

    Celsis, P.; Chan, M.; Marc-Vergnes, J.P.; Sveinsdottir, E.; Goldman, T.G.; Henriksen, L.; Paulson, O.B.; Stokely, E.M.; Lassen, N.A.

    1982-01-01

    This paper illustrates the capabilities of single-photon emission tomography in imaging local cerebral blood flows in man. The results purport the conclusion that a fairly good improvement has been achieved when compared to stationary detectors and that single-photon emission tomography is a well-suited tool for studying cerebral hemodynamics, especially within the framework of clinical studies [fr

  6. Distribution of the pulmonary blood flow measured by ECT

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, H.; Itoh, H.; Todo, Y.; Ishii, Y.; Mukai, T. (Kyoto Univ. (Japan). Hospital)

    1981-05-01

    Distributions of pulmonary blood flow per unit lung volume were observed by using the combination of Tc-99m-MAA and radionuclide CT. Administration of Tc-99m-MAA to the patients were performed in sitting position. Ten patients were studied with this method. In nine patients, the blood flow distribution was greater in the direction of the gravity, namely, more blood flow in the lower than the upper lung region. In six patients were demonstrated the relation between blood flow and the vertical distance described by West et al. Thus, it was possible to evaluate the arterial and venous pressures of the lung with the estimated pressure of 4.15 +- 1.93 cmH/sub 2/O and -5.55 +- 2.48 cmH/sub 2/O in relation to the angle of Louis. The agreement was reasonably well with that reported by Butler and Paley. Three patients had pulmonary hypertension with the distribution of monotonous increase, of which slope was similar to that of zone III in other six patients. The last patient with COPD had quite different distribution from other nine patients.

  7. Sympathetic regulation of cerebral blood flow in humans : a review

    NARCIS (Netherlands)

    ter Laan, M.; van Dijk, J. M. C.; Elting, J. W. J.; Staal, M. J.; Absalom, A. R.

    Cerebral blood flow (CBF) is regulated by vasomotor, chemical, metabolic, and neurogenic mechanisms. Even though the innervation of cerebral arteries is quite extensively described and reviewed in the literature, its role in regulation of CBF in humans remains controversial. We believe that

  8. A New Technology for Detecting Cerebral Blood Flow

    DEFF Research Database (Denmark)

    Schytz, Henrik W; Guo, Song; Jensen, Lars T

    2012-01-01

    There is a need for real-time non-invasive, continuous monitoring of cerebral blood flow (CBF) during surgery, in intensive care units and clinical research. We investigated a new non-invasive hybrid technology employing ultrasound tagged near infrared spectroscopy (UT-NIRS) that may estimate...

  9. Optically measured microvascular blood flow contrast of malignant breast tumors.

    Directory of Open Access Journals (Sweden)

    Regine Choe

    Full Text Available Microvascular blood flow contrast is an important hemodynamic and metabolic parameter with potential to enhance in vivo breast cancer detection and therapy monitoring. Here we report on non-invasive line-scan measurements of malignant breast tumors with a hand-held optical probe in the remission geometry. The probe employs diffuse correlation spectroscopy (DCS, a near-infrared optical method that quantifies deep tissue microvascular blood flow. Tumor-to-normal perfusion ratios are derived from thirty-two human subjects. Mean (95% confidence interval tumor-to-normal ratio using surrounding normal tissue was 2.25 (1.92-2.63; tumor-to-normal ratio using normal tissues at the corresponding tumor location in the contralateral breast was 2.27 (1.94-2.66, and using normal tissue in the contralateral breast was 2.27 (1.90-2.70. Thus, the mean tumor-to-normal ratios were significantly different from unity irrespective of the normal tissue chosen, implying that tumors have significantly higher blood flow than normal tissues. Therefore, the study demonstrates existence of breast cancer contrast in blood flow measured by DCS. The new, optically accessible cancer contrast holds potential for cancer detection and therapy monitoring applications, and it is likely to be especially useful when combined with diffuse optical spectroscopy/tomography.

  10. Cerebral blood flow in patients with dementia of Alzheimer's type

    DEFF Research Database (Denmark)

    Postiglione, A; Lassen, N A; Holman, B L

    1993-01-01

    In the normal brain as well as in Alzheimer's disease (AD), regional cerebral blood flow (CBF) is coupled to metabolic demand and, therefore, changes in CBF reflect variations in neuronal metabolism. The use of radionuclide techniques, such as positron emission tomography (PET) and single photon...

  11. Cerebral blood flow imaging with thallium-201 diethyldithiocarbamate SPECT

    NARCIS (Netherlands)

    van Royen, E. A.; de Bruïne, J. F.; Hill, T. C.; Vyth, A.; Limburg, M.; Byse, B. L.; O'Leary, D. H.; de Jong, J. M.; Hijdra, A.; van der Schoot, J. B.

    1987-01-01

    Thallium-201 diethyldithiocarbamate ([201TI]DDC) was studied in humans as an agent for cerebral blood flow imaging. Brain uptake proved to be complete 90 sec after injection with no appreciable washout or redistribution for hours. Intracarotid injection suggested an almost 100% extraction during the

  12. Patterns of regional cerebral blood flow in acute stroke

    DEFF Research Database (Denmark)

    Olsen, T S; Skriver, E B

    1981-01-01

    In a consecutive group of 56 stroke patients the regional cerebral blood flow was measured within 84 hours after stroke. A 254 multidetector scintillation camera and the intracarotid Xenon-133 injection method was used to study rCBF. Typical rCBF-patterns are described and compared to the findings...

  13. Determinants of resting cerebral blood flow in sickle cell disease

    NARCIS (Netherlands)

    Bush, Adam M.; Borzage, Matthew T.; Choi, Soyoung; Václavů, Lena; Tamrazi, Benita; Nederveen, Aart J.; Coates, Thomas D.; Wood, John C.

    2016-01-01

    Stroke is common in children with sickle cell disease and results from an imbalance in oxygen supply and demand. Cerebral blood flow (CBF) is increased in patients with sickle cell disease to compensate for their anemia, but adequacy of their oxygen delivery has not been systematically demonstrated.

  14. Velocity Profiles of Slow Blood Flow in a Narrow Tube

    Science.gov (United States)

    Chen, Jinyu; Huang, Zuqia; Zhuang, Fengyuan; Zhang, Hui

    1998-04-01

    A fractal model is introduced into the slow blood motion. When blood flows slowly in a narrow tube, red cell aggregation results in the formation of an approximately cylindrical core of red cells. By introducing the fractal model and using the power law relation between area fraction φ and distance from tube axis ρ, rigorous velocity profiles of the fluid in and outside the aggregated core and of the core itself are obtained analytically for different fractal dimensions. It shows a blunted velocity distribution for a relatively large fractal dimension (D ˜ 2), which can be observed in normal blood; a pathological velocity profile for moderate dimension (D = 1), which is similar to the Segre-Silberberg effect; and a parabolic profile for negligible red cell concentration (D = 0), which likes in the Poiseuille flow. The project supported by the National Basic Research Project "Nonlinear Science", National Natural Science Foundation of China and the State Education Commission through the Foundation of Doctoral Training

  15. Tubuloglomerular feedback dynamics and renal blood flow autoregulation in rats

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H; Wagner, A J; Marsh, D J

    1991-01-01

    To decide whether tubuloglomerular feedback (TGF) can account for renal autoregulation, we tested predictions of a TGF simulation. Broad-band and single-frequency perturbations were applied to arterial pressure; arterial blood pressure, renal blood flow and proximal tubule pressure were measured....... Data were analyzed by linear systems analysis. Broad-band forcings of arterial pressure were also applied to the model to compare experimental results with simulations. With arterial pressure as the input and tubular pressure, renal blood flow, or renal vascular resistance as outputs, the model...... correctly predicted gain and phase only in the low-frequency range. Experimental results revealed a second component of vascular control active at 100-150 mHz that was not predicted by the simulation. Forcings at single frequencies showed that the system behaves linearly except in the band of 33-50 m...

  16. Investigation of intrarenal blood flow and urine flow aspects by scintillation camera

    International Nuclear Information System (INIS)

    Kawamura, J.; Hosokawa, S.; Yoshida, O.; Ishii, Y.; Torizuka, K.

    1977-01-01

    In order to clarify intrarenal dynamic processes related to regional distribution in patients with unilateral renal disease, two radioactive tracers, 133 Xe and /sup 99m/Tc-diethylenetriaminepentaacetic acid (/sup 99m/Tc-DTPA) were introduced into a renal artery and intrarenal blood flow and urine flow aspects were observed by scintillation camera. Cortical blood flow decreased and medullary blood flow relatively increased with the advance of renal damage. Urine flow curve from normal cortex showed two phasic patterns. One early phase might correspond to the appearance of the tracer through the proximal tubule and a second phase might correspond to the appearance of the tracer through the loop of Henle to the distal tubule. Under mannitol diuresis, two phasic urine flow curves from the cortex became obscured and the peak time of pelvic curve shifted to the earlier period. These studies were considered to be useful in evaluating unilateral renal function and might offer a good insight for intrarenal physiology concerning blood flow as well as urine flow

  17. Effects of midazolam on cerebral blood flow in human volunteers

    International Nuclear Information System (INIS)

    Forster, A.; Juge, O.; Morel, D.

    1982-01-01

    The effects of intravenously administered midazolam on cerebral blood flow were evaluated in eight healthy volunteers using the 133 Xe inhalation technique. Six minutes after an intravenous dose of 0.15 mg/kg midazolam, the cerebral blood flow decreased significantly (P less than 0.001) from a value of 40.6 +/- 3.3 to a value of 27.0 +/- 5.0 ml . 100 g-1 . min-1. Cerebrovascular resistance (CVR) increased from 2.8 +/- 0.2 to 3.9 to 0.6 mmHg/(ml . 100 g-1 . min-1)(P less than 0.001). Mean arterial blood pressure decreased significantly (P less than 0.05) from 117 +/- 8 to 109 +/- 9 mmHg and arterial carbon dioxide tension increased from 33.9 +/- 2.3 to 38.6 +/- 3.2 mmHg (P less than 0.05). Arterial oxygen tension remained stable throughout the study, 484 +/- 95 mmHg before the administration of midazolam and 453 +/- 76 mmHg after. All the subjects slept after the injection of the drug and had anterograde amnesia of 24.5 +/- 5 min. The decrease in mean arterial blood pressure was probably not important since it remained in the physiologic range for cerebral blood flow autoregulation. The increase in arterial carbon dioxide tension observed after the midazolam injection may have partially counteracted the effect of this new benzodiazepine on cerebral blood flow. Our data suggest that midazolam might be a safe agent to use for the induction of anethesia in neurosurgical patients with intracranial hypertension

  18. Cerebral blood flow mapping in children with sickle cell disease

    International Nuclear Information System (INIS)

    Numaguchi, Y.; Humbert, J.R.; Robinson, A.E.; Lindstrom, W.W.; Gruenauer, L.M.

    1988-01-01

    A cerebral blood flow mapping system was applied to the evaluation of cerebral blood flow (CBF) in 21 patients with sickle cell cerebrovascular disease, by means of a Picker xenon computed tomographic (CT) scanner. Results indicate that (1) xenon CT is a safe and reliable procedure in children with cerebrovascular diseases; (2) CBF in the gray matter of children seems to be higher than in previously reported data obtained with use of isotopes; and (3) regional CBF can be altered significantly by changing the size of the region of interest (ROI). The term regional CBF probably has to be carefully defined in xenon CT flow mapping. Correlation with anatomy by means of CT or magnetic resonance imaging and comparison with the ROI of the contralateral side and/or adjacent sections is important

  19. Determination of uteroplacental blood flow by a radionuclide technique

    International Nuclear Information System (INIS)

    Rosati, P.; Exacuostos, C.; Bellati, U.; Maini, C.L.; Bonetti, M.G.; Galli, G.

    1987-01-01

    The placental blood flow was determined using a non-invasive radioisotopic approach, with the intravenous administration of 113m In (37 MBq). The method was employed in 20 normal pregnancies, in 24 patients with intrauterine growth retardation, in 8 patients with iso-Rh-incompatibility and in 9 patients with gestational diabetes. In the group with intrauterine growth retardation 2 pregnancies with extensive fetal malformations were included. In one case without evident histological placental alteration the index was 3.94 at 34 weeks of gestation and 5.62 at 36 weeks of gestation. In the second one with placental infarcts the index was 3.46 at 38 weeks of gestation. Normal pregnancies showed a flow index of 5.50 ± 1.57 units compared to the pathological pregnancies value of 2.74 ± 0.90 units. The method is very well suited to clinical evaluation of placental blood flow. (author)

  20. Neonatal changes in renal blood flow distribution in puppies

    International Nuclear Information System (INIS)

    Aschinberg, L.C.; Goldsmith, D.I.; Olbing, H.; Spitzer, A.; Edelmann, C.M. Jr.; Blaufox, M.D.

    1975-01-01

    The intrarenal distribution of blood flow was studied in 31 newborn mongrel puppies from 18 h to 70 days using xenon washout and krypton autoradiography. Mean renal blood flow increased from 0.39 +- 0.05 ml/g per min (SE) the 1st wk to 2.06 +- 0.12 ml/g per min at 6 wk. During the 1st wk of life the renal cortex was perfused homogeneously at 0.88 +- 0.19 ml/g min (SE) and accounted for 35 +- 4 percent of the renal blood flow. During the 2nd wk a narrow, rapidly perfused zone of outer cortex was identified which was perfused at 3.35 +- 0.26 ml/g per min, received 19.53 +- 5.05 percent of the total renal blood flow, and represented 15 +- 4 percent of the mass of the total cortex. The inner cortex and outer medulla at this time received 53.40 +- 4.12 percent of the flow at 1.07 +- 0.08 ml/g per min. Outer cortical flow increased with age reaching adult values by about 6 to 10 wk when the rapidly perfused area represented 40 +- 8 percent of the cortex. These changes are parallel to the results of previously reported studies with microspheres in newborn puppies and are compatible with the well-established maturational changes noted in neonates of several species. They represent the first gas-washout studies in animals during the first 6 wk of life

  1. Cerebral blood flow in migraine and cortical spreading depression

    Energy Technology Data Exchange (ETDEWEB)

    Lauritzen, M.

    1987-01-01

    In a series of migraine patients, carotid arteriography was carried out as part of the clinical evalution. Nine patients developed a migrainous attack with focal neurological symptoms and headache after the angiography and during the subsequent, ongoing regional cerebral blood flow rCBF study. rCBF was measured by bolus injection of Xenon/sup 133/ into the internal carotid artery and a gamma camera with 254 collimated scintillation detectors covering the lateral aspect of the hemisphere. This technique depicts rCBF mainly at the level of the superficial cortex, with no depth resolution. The resolution is 1 cm/sup 2/ providing detailed spatial information of the cortical blood flow. Other methods for measuring local blood flow in animal and man employ a radioactive, freely diffusible tracer, in combination with an autoradiographic technique for the assessment of the tissue concentration, the so-called autoradiographic methods. In the series of patients with spontaneous migraine, rCBF was estimated using an in-vivo application of the autoradiographic principle. Xenon/sup 133/ was administered by inhalation and the time course of the arterial concentration curve was assessed by a scintillation detector over the upper right lung, since the arterial curve has been found to follow the shape of the lung curve. The rCBF was studied accompanying cortical spreading depression in rat experiments to evaluate wheter this phenomenon could explain the blood flow changes in migraine. (/sup 14/C) iodoantipyrine was given as an intravenous bolus injection and the brain content of indicator was determined by tissue sample or autoradiography after 10 or 20 seconds of isotope circulation. The conditions of the autoradiographic methods are that the flow remains constant within the period of measuring, and that the region under study is homogenous with regard to flow and lambda. (EG).

  2. Influence of Gravity on Blood Volume and Flow Distribution

    Science.gov (United States)

    Pendergast, D.; Olszowka, A.; Bednarczyk, E.; Shykoff, B.; Farhi, L.

    1999-01-01

    In our previous experiments during NASA Shuttle flights SLS 1 and 2 (9-15 days) and EUROMIR flights (30-90 days) we observed that pulmonary blood flow (cardiac output) was elevated initially, and surprisingly remained elevated for the duration of the flights. Stroke volume increased initially and then decreased, but was still above 1 Gz values. As venous return was constant, the changes in SV were secondary to modulation of heart rate. Mean blood pressure was at or slightly below 1 Gz levels in space, indicating a decrease in total peripheral resistance. It has been suggested that plasma volume is reduced in space, however cardiac output/venous return do not return to 1 Gz levels over the duration of flight. In spite of the increased cardiac output, central venous pressure was not elevated in space. These data suggest that there is a change in the basic relationship between cardiac output and central venous pressure, a persistent "hyperperfusion" and a re-distribution of blood flow and volume during space flight. Increased pulmonary blood flow has been reported to increase diffusing capacity in space, presumably due to the improved homogeneity of ventilation and perfusion. Other studies have suggested that ventilation may be independent of gravity, and perfusion may not be gravity- dependent. No data for the distribution of pulmonary blood volume were available for flight or simulated microgravity. Recent studies have suggested that the pulmonary vascular tree is influenced by sympathetic tone in a manner similar to that of the systemic system. This implies that the pulmonary circulation is dilated during microgravity and that the distribution of blood flow and volume may be influenced more by vascular control than by gravity. The cerebral circulation is influenced by sympathetic tone similarly to that of the systemic and pulmonary circulations; however its effects are modulated by cerebral autoregulation. Thus it is difficult to predict if cerebral perfusion is

  3. Spatial Temporal Image Correlation Spectroscopy (STICS) for Flow Analysis with Application for Blood Flow Mapping

    International Nuclear Information System (INIS)

    Rossow, Molly; Gratton, Enrico; Mantulin, William M.

    2009-01-01

    It is important for surgeons to be able to measure blood flow in exposed arterioles during surgery. We report our progress in the development of an optical technique that will measure blood flow in surgically exposed blood vessels and enable previously difficult measurements. By monitoring optical fluctuations, the optical technique, based on Spatial Temporal Image Correlation (STICS), will directly measure the velocity of micron-scale particles--such as red blood cells. It will complement existing technology and provide qualitative measurements that were not previously possible. It relies on the concept that blood, when viewed on a small enough scale, is an inhomogeneous substance. Individual blood cells passing between a near-infrared light source and a detector will cause fluctuations in the transmitted optical signal. The speed, direction, and flow pattern of blood cells can be determined from these optical fluctuations. We present a series of computer simulations and experiments on phantom and animal systems to test this technique's ability to map complex flow patterns.

  4. Spatial Temporal Image Correlation Spectroscopy (STICS) for Flow Analysis with Application for Blood Flow Mapping (abstract)

    Science.gov (United States)

    Rossow, Molly; Mantulin, William M.; Gratton, Enrico

    2009-04-01

    It is important for surgeons to be able to measure blood flow in exposed arterioles during surgery. We report our progress in the development of an optical technique that will measure blood flow in surgically exposed blood vessels and enable previously difficult measurements. By monitoring optical fluctuations, the optical technique, based on Spatial Temporal Image Correlation (STICS), will directly measure the velocity of micron-scale particles-such as red blood cells. It will complement existing technology and provide qualitative measurements that were not previously possible. It relies on the concept that blood, when viewed on a small enough scale, is an inhomogeneous substance. Individual blood cells passing between a near-infrared light source and a detector will cause fluctuations in the transmitted optical signal. The speed, direction, and flow pattern of blood cells can be determined from these optical fluctuations. We present a series of computer simulations and experiments on phantom and animal systems to test this technique's ability to map complex flow patterns.

  5. [Assessment of maternal cerebral blood flow in patients with preeclampsia].

    Science.gov (United States)

    Mandić, Vesna; Miković, Zeljko; Dukić, Milan; Vasiljević, Mladenko; Filimonović, Dejan; Bogavac, Mirjana

    2005-01-01

    Systemic vasoconstriction in preeclamptic patients increases vascular resistance, and is manifested by increased arterial blood flow velocity. The aim of the study is to evaluate if there is a change of Doppler indices in maternal medial cerbral artery (MCA) in severe preeclampsia due to: 1) severity of clinical symptoms, 2) the begining of eclamptic attack and 3) the application of anticonvulsive therapy. A prospective clinical study included 92 pregnant women, gestational age 28-36 weeks. They were divided into three groups: normotensive (n=30), mild preeclampsia (n=33), and severe preeclampsia (n=29). We investigated maternal cerebral circulation by assessing the MCA. We registrated: pulsatility index (Pi), resistance index (Ri), systolic/diastolic ratio (S/D), and the maximum systolic, end diastolic and medium velocity. Patients with severe preeclampsia were divided into two subgroups. subgroup 1 included patients without symptoms of threatening eclampsia (n=18; 62.06%); while subgroup 2 included those with symptoms of preeclampsia (n=11; 37.94%). All patients with severe preeclampsia were treated with magnesium sulfate (MgSO4), and cerebral blood flow was measured before and after the treatment. Statistical analysis was done by oneway ANOVA, Student t-test and t-paired sample test. The difference was considered to be significant if ppreclampsia we found increased velocity values, Pi and Ri, especially in patients with signs of threatened eclampsia, suggesting that blood vessels changes are most prominent in severe preeclampsia. Cerebral blood flow meassurements can be used as a clinical test for the prediction of eclampsia. Magnesium-sulfate (MgSO4) has a signifficant role in prophylaxis and treatment of eclampsia, and, therefore, positive influence on reduction of cerebral ishemic lesions can be expected. We can conclude that changes of the cerebral blood flow can be evaluated by evaluating blood flow velocities in the medial cerebral artery. Velocities tend

  6. Kidney Rehabilitation Technology by Improving Blood Flow and Nerve Activation

    International Nuclear Information System (INIS)

    Mohd Jamil Hashim

    2016-01-01

    The rehabilitation of kidney is impossible from doctors point of view. Kidney failure happens when nephron in kidney fail to filter blood and water. Two major causes of kidney failure. First is the shrinkage of kidney and the second is the blockage of kidney medulla. Kidney shrinkage is because nephron damage due to long term diabetes (Nephrology expert point of view). Whereas blockage of kidney is due to food consume which in turn build up deposit at the blood duct connecting to the medulla. Experiment specimen own body. The rehabilitation methodology is to build up your blood flow system and nerve activation. Result from the study is through analyzing blood components such as creatinine, hemoglobin, urea and potassium. Conclusion, creatinine value has lowered and kidney shrinkage has normalize to its original size. It is hopeful I regain my health 100 % when my GFR reading achieved below 100. (author)

  7. Skeletal blood flow, iliac histomorphometry, and strontium kinetics in osteoporosis: a relationship between blood flow and corrected apposition rate

    International Nuclear Information System (INIS)

    Reeve, J.; Arlot, M.; Wootton, R.; Edouard, C.; Tellez, M.; Hesp, R.; Green, J.R.; Meunier, P.J.

    1988-01-01

    In 20 untreated patients with idiopathic or postmenopausal osteoporosis, kinetic studies of skeletal blood flow (using 18 F) and bone turnover (using 85 Sr) were combined with dynamic histomorphometry performed on transiliac biopsies taken within 6 weeks of each other. In 8 patients the combined studies were repeated after treatment. A further 5 patients were studied only while receiving treatment. As expected, skeletal blood flow measured by 18 F correlated with an index of 85 Sr uptake into the exchangeable pools of bone. Additionally and independently, skeletal blood flow correlated with an index of the work rate of the osteoblasts in each multicellular unit of bone (the corrected apposition rate of Parfitt). These correlations were statistically significant in both the untreated patients (P less than 0.05) and the whole group (P less than 0.001). Further indices related to bone turnover at the level of the skeleton as a whole were significantly associated with skeletal blood flow only in the combined group

  8. Blood flow quantification using 1D CFD parameter identification

    Science.gov (United States)

    Brosig, Richard; Kowarschik, Markus; Maday, Peter; Katouzian, Amin; Demirci, Stefanie; Navab, Nassir

    2014-03-01

    Patient-specific measurements of cerebral blood flow provide valuable diagnostic information concerning cerebrovascular diseases rather than visually driven qualitative evaluation. In this paper, we present a quantitative method to estimate blood flow parameters with high temporal resolution from digital subtraction angiography (DSA) image sequences. Using a 3D DSA dataset and a 2D+t DSA sequence, the proposed algorithm employs a 1D Computational Fluid Dynamics (CFD) model for estimation of time-dependent flow values along a cerebral vessel, combined with an additional Advection Diffusion Equation (ADE) for contrast agent propagation. The CFD system, followed by the ADE, is solved with a finite volume approximation, which ensures the conservation of mass. Instead of defining a new imaging protocol to obtain relevant data, our cost function optimizes the bolus arrival time (BAT) of the contrast agent in 2D+t DSA sequences. The visual determination of BAT is common clinical practice and can be easily derived from and be compared to values, generated by a 1D-CFD simulation. Using this strategy, we ensure that our proposed method fits best to clinical practice and does not require any changes to the medical work flow. Synthetic experiments show that the recovered flow estimates match the ground truth values with less than 12% error in the mean flow rates.

  9. Three-dimensional imaging of absolute blood flow velocity and blood vessel position under low blood flow velocity based on Doppler signal information included in scattered light from red blood cells

    Science.gov (United States)

    Kyoden, Tomoaki; Akiguchi, Shunsuke; Tajiri, Tomoki; Andoh, Tsugunobu; Hachiga, Tadashi

    2017-11-01

    The development of a system for in vivo visualization of occluded distal blood vessels for diabetic patients is the main target of our research. We herein describe two-beam multipoint laser Doppler velocimetry (MLDV), which measures the instantaneous multipoint flow velocity and can be used to observe the blood flow velocity in peripheral blood vessels. By including a motorized stage to shift the measurement points horizontally and in the depth direction while measuring the velocity, the path of the blood vessel in the skin could be observed using blood flow velocity in three-dimensional space. The relationship of the signal power density between the blood vessel and the surrounding tissues was shown and helped us identify the position of the blood vessel. Two-beam MLDV can be used to simultaneously determine the absolute blood flow velocity distribution and identify the blood vessel position in skin.

  10. Blood transfusion in preterm infants improves intestinal tissue oxygenation without alteration in blood flow.

    Science.gov (United States)

    Banerjee, J; Leung, T S; Aladangady, N

    2016-11-01

    The objective of the study was to investigate the splanchnic blood flow velocity and oximetry response to blood transfusion in preterm infants according to postnatal age. Preterm infants receiving blood transfusion were recruited to three groups: 1-7 (group 1; n = 20), 8-28 (group 2; n = 21) and ≥29 days of life (group 3; n = 18). Superior mesenteric artery (SMA) peak systolic (PSV) and diastolic velocities were measured 30-60 min pre- and post-transfusion using Doppler ultrasound scan. Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) were measured from 15-20 min before to post-transfusion using near-infrared spectroscopy. The mean pretransfusion Hb in group 1, 2 and 3 was 11, 10 and 9 g/dl, respectively. The mean (SD) pretransfusion SMA PSV in group 1, 2 and 3 was 0·63 (0·32), 0·81 (0·33) and 0·97 (0·40) m/s, respectively, and this did not change significantly following transfusion. The mean (SD) pretransfusion sTOI in group 1, 2 and 3 was 36·7 (19·3), 44·6 (10·4) and 41·3 (10·4)%, respectively. The sTHI and sTOI increased (P transfusion in all groups. On multivariate analysis, changes in SMA PSV and sTOI following blood transfusion were not associated with PDA, feeding, pretransfusion Hb and mean blood pressure. Pretransfusion baseline splanchnic tissue oximetry and blood flow velocity varied with postnatal age. Blood transfusion improved intestinal tissue oxygenation without altering mesenteric blood flow velocity irrespective of postnatal ages. © 2016 International Society of Blood Transfusion.

  11. [Prognostic Doppler ultrasound examination of fetal arteries blood flow].

    Science.gov (United States)

    Sieroszewski, Piotr; Sabatowska, Małgorzata; Karowicz-Bilińska, Agata; Suzin, Jacek

    2002-08-01

    Early detection of fetal risk is one of the main issues in today obstetrics. Ultrasound diagnostics plays a significant role, as the introduction of Doppler imaging method in the evaluation of blood flow has enabled non-invasive assessment of uteroplacental circulation. Therefore, we have analysed foetal three arteries: umbilical artery, middle cerebral artery and renal artery after determining the normal range for the analysed parameters. 1. Comparison of the obtained blood flow indices (S/D, RI, PI) in the umbilical artery, middle cerebral artery and renal artery of foetuses from normal and complicated full-term pregnancies. 2. Determination of indices: umbilical-cerebral and renal-cerebral in normal and pathological pregnancy. 3. Evaluation of feasibility of the analysed flow parameters for the detection of intrauterine foetal hypoxia. We have examined 151 women, who were divided into control group--101 pregnant women with normal pregnancy and study group--50 pregnant women with complicated pregnancy. All pregnant women underwent ultrasound examination using the Hitachi EUB 515 C (Japan) scanner with 3.5 MHz convex probe, connected to the colour pulsed Doppler. The study consisted of the biometric measurements and evaluation of the spectrum of blood flow in the umbilical artery, middle cerebral artery and renal artery. We have determined following indices: a) systolic-diastolic ratio S/D, resistance index RI, pulsatility index PI, b) umbilical-cerebral ratio P/M. (PI ua/PI mca), renal--cerebral ratio N/M (PI ra/PI mca). Statistically significant difference was found between the study and control groups for all the flow indices assessed (S/D, RI, PI) for the middle cerebral artery, for the indices P/M and N/M. (p < 0.001) and pulsatility index in the renal artery (p < 0.01). Similar, although slightly smaller difference (p < 0.05) was seen for the values of flow parameters in the umbilical artery. 1) Evaluation of blood flow in the middle cerebral artery, and in

  12. Modulation of radial blood flow during Braille character discrimination task.

    Science.gov (United States)

    Murata, Jun; Matsukawa, K; Komine, H; Tsuchimochi, H

    2012-03-01

    Human hands are excellent in performing sensory and motor function. We have hypothesized that blood flow of the hand is dynamically regulated by sympathetic outflow during concentrated finger perception. To identify this hypothesis, we measured radial blood flow (RBF), radial vascular conductance (RVC), heart rate (HR), and arterial blood pressure (AP) during Braille reading performed under the blind condition in nine healthy subjects. The subjects were instructed to read a flat plate with raised letters (Braille reading) for 30 s by the forefinger, and to touch a blank plate as control for the Braille discrimination procedure. HR and AP slightly increased during Braille reading but remained unchanged during the touching of the blank plate. RBF and RVC were reduced during the Braille character discrimination task (decreased by -46% and -49%, respectively). Furthermore, the changes in RBF and RVC were much greater during the Braille character discrimination task than during the touching of the blank plate (decreased by -20% and -20%, respectively). These results have suggested that the distribution of blood flow to the hand is modulated via sympathetic nerve activity during concentrated finger perception.

  13. The interactive effects of a gradual temperature decrease and long-term food deprivation on cardiac and hepatic blood flows in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Petersen, L H; Dzialowski, E; Huggett, D B

    2011-11-01

    The aim of the present study was to determine the extent to which the fish liver is perfused with blood. Transonic® flow probes were therefore implanted around the ventral aorta and hepatic vein(s) to record baseline blood flows in rainbow trout (Oncorhynchus mykiss) previously held under two different feeding regimes (food-deprived or fed to satiation, 8-12 weeks). Fish from both groups were exposed to a gradual temperature decrease (12°C to 5°C) and physical disturbance. Cardiac output (Q), stroke volume (Sv) and hepatic venous blood flow (HVBF) were significantly reduced in food-deprived trout at 12°C. Heart rate was not significantly affected by nutritional status, but was significantly reduced when temperature was decreased to 5°C. Physically disturbing each fish at 12°C and 5°C showed that the performance capacity of the heart was not affected by food deprivation as the capacity to increase Q and Sv was not reduced in the food-deprived group. Overall this study showed that food deprivation in rainbow trout reduced cardiac and hepatic blood flows. However, long-term food deprivation did not affect the capacity of the heart to acutely increase performance. Copyright © 2011. Published by Elsevier Inc.

  14. The impact of intrahepatic microcapsule transplantation on the liver function and liver blood flow: a comparative study of different transplantation approaches

    International Nuclear Information System (INIS)

    Ai Zhaodong; Wang Wei; Gao Feng; Rong Pengfei; Zheng Wei; Dong Qiong; Liu Sheng

    2011-01-01

    Objective: to compare the impact of intrahepatic microcapsule transplantation on the liver function and liver blood flow between via portal vein approach and via hepatic artery approach. Methods: Twenty healthy male dogs were randomly and equally divided into four groups: A1, A2, V1 and V2. For group V1 and group V2, the microcapsules were implanted into portal vein through percultaneous transhepatic approach under ultrasonographic guidance, while for group A1 and group A2, the microcapsules were implanted into hepatic artery through hepatic artery catheterization. The quantity of microcapsules implanted into group A1 and group A2 was 32000 microcapsule/Kg and 48000 microcapsule/Kg respectively, while for group V1 and group V2 was 16000 microcapsule/Kg and 32000 microcapsule/Kg respectively. Before, during and after the microcapsule transplantation ultrasonography was performed to determine the hepatic blood flow rate as well as the diameter of the portal vein. ALT, AST and the main serum liver fibrosis indexes were measured before and after the transplantation. Samples of the livers were pathologically examined before and after the operation. The results were compared between each group. Results: No significant changes in blood flow rate of main portal vein was found after the transplantation in both group A1 and group A2. In both group V1 and group V2 the blood flow of main portal vein became slow during the procedure but recovered quickly. No significant difference in portal blood flow rate existed between each group one week after the operation (P>0.05). Shortly after the transplantation the ALT and AST levels showed an increase of different degree in all dogs, which reached its peak at 24 hours after the operation. The increase in ALT and AST levels was most sharp in group V2 while most minor in group A1. The ALT and AST levels gradually returned to normal two weeks later. The difference in ALT and AST levels between every group was significant (P<0

  15. Blood flow changes in Alzheimer's disease induced by lactate

    International Nuclear Information System (INIS)

    Pavics, L.; Sera, T.; Kalman, J.; Janka, Z.; Csernay, L.

    2002-01-01

    Full text: Lactate, as metabolite of the glycolysis is a source of energy of the nerves. In vitro and in vivo experiments showed the neuroprotective effect of lactate and improvement of brain function after ischaemic injury. Intravenous infusion of lactate increases the global cerebral blood flow (CBF). In Alzheimer disease (AD) characteristic regional blood flow abnormalities and in the cerebrospinal fluid abnormal lactate levels were detected. Since disturbed CBF and vasoregulation was found in AD the effect of intravenous Na-lactate on CBF and related metabolic parameters was examined in order to assess the CBF response in the AD brain. In twenty (14 woman, 6 man, age ± SD.: 74 ± 7 years) patients with Alzheimer's disease (DSM IV, MMT.:13 ± 6) self-control study was performed. rCBF SPECT (99mTc-HMPAO) investigations were fulfilled during 5 mg/kg body weight 0.5 M Na-lactate infusion and in control state (0.9 % saline infusion) one week apart. The rCBF changes visually and by statistical parametric mapping were analyzed. ECG, blood pressure, heart rate, venous blood pH, pCO 2 , bicarbonate, serum lactate and cortisol level were measured before and after the SPECT investigation. Acute panic inventory and anxiety rating scales were used to access the psychiatric effect of lactate. The serum lactate levels increased in average from 0.8 mmol/L to 4.6 mmol/L, and 6.1 mmol/L 10 and 20 minutes after lactate infusion respectively. Compensatory changes were found in the venous blood pH, pCO 2 and bicarbonate levels. Significant psychiatric symptoms and blood pressure and heart rate increase were not observed. The serum cortisol level remained unchanged. At the baseline investigation all of the patients have bilateral temporal or parietal hypoperfused areas in 8 patients with other additional localization of abnormalities. In 12 patients the global cerebral blood flow increased, in 8 decreased rCBF was detected by visual evaluation. According to the SPM analysis the

  16. A numerical study of blood flow using mixture theory

    OpenAIRE

    Wu, Wei-Tao; Aubry, Nadine; Massoudi, Mehrdad; Kim, Jeongho; Antaki, James F.

    2014-01-01

    In this paper, we consider the two dimensional flow of blood in a rectangular microfluidic channel. We use Mixture Theory to treat this problem as a two-component system: One component is the red blood cells (RBCs) modeled as a generalized Reiner–Rivlin type fluid, which considers the effects of volume fraction (hematocrit) and influence of shear rate upon viscosity. The other component, plasma, is assumed to behave as a linear viscous fluid. A CFD solver based on OpenFOAM® was developed and ...

  17. Cerebral blood flow measurement in cerebrovascular occlusive diseases

    International Nuclear Information System (INIS)

    Yanagihara, T.; Wahner, H.W.

    1984-01-01

    In order to evaluate cerebral blood flow (CBF) patterns among individual patients with increased statistical confidence, CBF measurements were carried out using the 133Xe-inhalation method and external head detectors. F1 values representing gray matter flow from 3 to 6 head detectors were averaged to form 16 different regions for each cerebral hemisphere. Normative values were obtained from 46 healthy volunteers, and data from individual regions were analyzed for absolute blood flow rates (ml/100g/min), for concordance between right and left hemispheres and as percent of mean hemispheric flow. CBF measurements were then carried out among 37 patients with cerebrovascular occlusive diseases, and results were compared with normative values. A high incidence of abnormal flows were detected among symptomatic patients with intracranial arterial stenosis or occlusion and those with extracranial internal carotid artery occlusion. By using the above method for data analysis, it was possible to delineate hypoperfused areas among these patients. Even though the 133Xe-inhalation method has inherent limitations, this is a practical and safe method for measurement of CBF which can provide reliable information useful for management of patients with cerebrovascular occlusive diseases, particularly when the results are presented with statistical confidence

  18. FDM Analysis for Blood Flow through Stenosed Tapered Arteries

    Directory of Open Access Journals (Sweden)

    Sankar DS

    2010-01-01

    Full Text Available Abstract A computational model is developed to analyze the unsteady flow of blood through stenosed tapered narrow arteries, treating blood as a two-fluid model with the suspension of all the erythrocytes in the core region as Herschel-Bulkley fluid and the plasma in the peripheral layer as Newtonian fluid. The finite difference method is employed to solve the resulting system of nonlinear partial differential equations. The effects of stenosis height, peripheral layer thickness, yield stress, viscosity ratio, angle of tapering and power law index on the velocity, wall shear stress, flow rate and the longitudinal impedance are analyzed. It is found that the velocity and flow rate increase with the increase of the peripheral layer thickness and decrease with the increase of the angle of tapering and depth of the stenosis. It is observed that the flow rate decreases nonlinearly with the increase of the viscosity ratio and yield stress. The estimates of the increase in the longitudinal impedance to flow are considerably lower for the two-fluid Herschel-Bulkley model compared with those of the single-fluid Herschel-Bulkley model. Hence, it is concluded that the presence of the peripheral layer helps in the functioning of the diseased arterial system.

  19. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, Zoran [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Roessle, Martin; Schultheiss, Michael [University Medical Center Freiburg, Department of Gastroenterology, Freiburg (Germany); Euringer, Wulf; Langer, Mathias [University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Salem, Riad; Barker, Alex; Carr, James; Collins, Jeremy D. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2015-09-15

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  20. Analysis of liver blood flow by dynamic hepatic scintigraphy

    International Nuclear Information System (INIS)

    Xie Tianhao; Jia Shiquan

    1996-01-01

    Liver blood flow was studied in 45 patients with solitary malignant liver cancer, 17 patients with multiple liver metastases, 18 patients with benign liver tumor and 20 control subjects by dynamic hepatic scintigraphy. The hepatic perfusion index (HPI) in control subjects, patients with liver malignant cancer and benign tumor was 0.33 +- 0.069, 0.589 +- 0.084, 0.384 +-0.046 respectively, and the mesenteric fraction (MF) was 0.56 +- 0.054, 0.246 +- 0.064, 0.524 +- 0.086 respectively. In conclusion, flow scintigraphy is a non-invasive, sensitive and repeatable method for detection of liver tumor

  1. Acute reductions in blood flow restricted to the dorsomedial medulla induce a pressor response in rats.

    Science.gov (United States)

    Waki, Hidefumi; Bhuiyan, Mohammad E R; Gouraud, Sabine S; Takagishi, Miwa; Hatada, Atsutoshi; Kohsaka, Akira; Paton, Julian F R; Maeda, Masanobu

    2011-08-01

    The brainstem nucleus of the solitary tract (nucleus tractus solitarii, NTS) is a pivotal region for regulating the set-point of arterial pressure, the mechanisms of which are not fully understood. Based on evidence that the NTS exhibits O2-sensing mechanisms, we examined whether a localized disturbance of blood supply, resulting in hypoxia in the NTS, would lead to an acute increase in arterial pressure. Male Wistar rats were used. Cardiovascular parameters were measured before and after specific branches of superficial dorsal medullary veins were occluded; we assumed these were drainage vessels from the NTS and would produce stagnant hypoxia. Hypoxyprobe-1, a marker for detecting cellular hypoxia in the post-mortem tissue, was used to reveal whether vessel occlusion induced hypoxia within the NTS. Following vessel occlusion, blood flow in the dorsal surface of the medulla oblongata including the NTS region showed an approximately 60% decrease and was associated with hypoxia in neurons located predominantly in the caudal part of the NTS as revealed using hypoxyprobe-1. Arterial pressure increased and this response was pronounced significantly in both magnitude and duration when baroreceptor reflex afferents were sectioned. These results suggest that localized hypoxia in the NTS increases arterial pressure. We suggest this represents a protective mechanism whereby the elevated systemic pressure is a compensatory mechanism to enhance cerebral perfusion. Whether this physiological mechanism has any relevance to neurogenic hypertension is discussed.

  2. The measurement of limb blood flow using technetium-labelled red blood cells

    International Nuclear Information System (INIS)

    Parkin, A; Robinson, P.J.; Wiggins, P.A.; Leveson, S.H.; Salter, M.C.P.; Matthews, I.F.; Ware, F.M.

    1986-01-01

    A method for measuring blood flow below the knee during reactive hyperaemia induced by 3 min of arterial occlusion has been developed. Subjects are positioned with lower limbs within the field of view of a gamma camera and pneumatic cuffs are placed below the knees to isolate the blood and induce a hyperaemic response. The remaining blood pool is labelled with 99 Tcsup(m)-labelled red cells. Blood flows have been derived from the initial gradients of time-activity curves and from equilibrium blood sampling. The technique has been validated using a tissue-equivalent leg phantom and peristaltic pump. The method has been applied to a small group of patients with peripheral vascular disease and to normal controls. The mean value (+-SD) of limb perfusion for normal controls was found to be 16.4+-3.0 ml/100 ml/min and for patients with intermittent claudication was 5.1+-2.6 ml/100 ml/min. Flow measurements are found to correlate with clinical findings and with symptoms. Reproducibility (established by repeated measurements) is high. The method is well tolerated even by patients suffering from rest pain. (author)

  3. Measurement of limb blood flow using technetium-labelled red blood cells

    Energy Technology Data Exchange (ETDEWEB)

    Parkin, A; Robinson, P.J.; Wiggins, P.A.; Leveson, S.H.; Salter, M.C.P.; Matthews, I.F.; Ware, F.M.

    1986-05-01

    A method for measuring blood flow below the knee during reactive hyperaemia induced by 3 min of arterial occlusion has been developed. Subjects are positioned with lower limbs within the field of view of a gamma camera and pneumatic cuffs are placed below the knees to isolate the blood and induce a hyperaemic response. The remaining blood pool is labelled with /sup 99/Tcsup(m)-labelled red cells. Blood flows have been derived from the initial gradients of time-activity curves and from equilibrium blood sampling. The technique has been validated using a tissue-equivalent leg phantom and peristaltic pump. The method has been applied to a small group of patients with peripheral vascular disease and to normal controls. The mean value (+-SD) of limb perfusion for normal controls was found to be 16.4 +- 3.0 ml/100 ml/min and for patients with intermittent claudication was 5.1 +- 2.6 ml/100 ml/min. Flow measurements are found to correlate with clinical findings and with symptoms. Reproducibility (established by repeated measurements) is high. The method is well tolerated even by patients suffering from rest pain.

  4. Regional blood flow distribution and oxygen metabolism during mesenteric ischemia and congestion.

    Science.gov (United States)

    Cruz, Ruy J; Garrido, Alejandra G; Ribeiro, Cristiane M F; Harada, Tomoyuki; Rocha-e-Silva, Mauricio

    2010-06-01

    Acute mesenteric ischemia is a potentially fatal vascular emergency with mortality rates ranging between 60% and 80%. Several studies have extensively examined the hemodynamic and metabolic effects of superior mesenteric artery occlusion. On the other hand, the cardiocirculatory derangement and the tissue damage induced by intestinal outflow obstruction have not been investigated systematically. For these reasons we decided to assess the initial impact of venous mesenteric occlusion on intestinal blood flow distribution, and correlate these findings with other systemic and regional perfusion markers. Fourteen mongrel dogs were subjected to 45 min of superior mesenteric artery (SMAO) or vein occlusion (SMVO), and observed for 120 min after reperfusion. Systemic hemodynamics were evaluated using Swan-Ganz and arterial catheters. Regional blood flow (ultrasonic flow probes), intestinal O(2)-derived variables, and mesenteric-arterial and tonometric-arterial pCO(2) gradients (D(mv-a)pCO(2) and D(t-a)pCO(2)) were also calculated. SMVO was associated with hypotension and low cardiac output. A significant increase in the regional pCO(2) gradients was also observed in both groups during the ischemic period. After reperfusion, a progressive reduction in D(mv-a)pCO(2) occurred in the SMVO group; however, no improvement in D(t-a)pCO(2) was observed. The histopathologic injury scores were 2.7 +/- 0.5 and 4.8 +/- 0.2 for SMAO and SMVO, respectively. SMV occlusion promoted early and significant hemodynamic and metabolic derangement at systemic and regional levels. Additionally, systemic pCO(2) gradient is not a reliable parameter to evaluate the local intestinal oxygenation. Finally, the D(t-a)pCO(2) correlates with histologic changes during intestinal congestion or ischemia. However, minor histologic changes cannot be detected using this methodology. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  5. Renal vein oxygen saturation in renal artery stenosis

    DEFF Research Database (Denmark)

    Nielsen, K; Rehling, M; Henriksen, Jens Henrik Sahl

    1992-01-01

    Renal vein oxygen-saturation was measured in 56 patients with arterial hypertension and unilateral stenosis or occlusion of the renal artery. Oxygen-saturation in blood from the ischaemic kidney (84.4%, range 73-93%) was significantly higher than that from the 'normal' contralateral kidney (81...... than its blood flow. This is probably due to decreased filtration fraction and filtered sodium with subsequent reduction in absolute tubular re-absorption of sodium ions....

  6. Subcutaneous blood flow in early male pattern baldness

    International Nuclear Information System (INIS)

    Klemp, P.; Peters, K.; Hansted, B.

    1989-01-01

    The subcutaneous blood flow (SBF) was measured by the 133 Xe washout method in the scalp of 14 patients with early male pattern baldness. Control experiments were performed in 14 normal haired men matched for age. The SBF in the scalp of the normal individuals was about 10 times higher than previously reported SBF values in other anatomical regions. In patients with early male pattern baldness, SBF was 2.6 times lower than the values found in the normal individuals (13.7 +/- 9.6 vs 35.7 +/- 10.5 ml/100 g/min-1). This difference was statistically significant (p much less than 0.001). A reduced nutritive blood flow to the hair follicles might be a significant event in the pathogenesis of early male pattern baldness

  7. Coded Ultrasound for Blood Flow Estimation Using Subband Processing

    DEFF Research Database (Denmark)

    Gran, Fredrik; Udesen, Jesper; Nielsen, Michael Bachamnn

    2008-01-01

    the excitation signal is broadband and has good spatial resolution after pulse compression. This means that time can be saved by using the same data for B-mode imaging and blood flow estimation. Two different coding schemes are used in this paper, Barker codes and Golay codes. The performance of the codes......This paper investigates the use of coded excitation for blood flow estimation in medical ultrasound. Traditional autocorrelation estimators use narrow-band excitation signals to provide sufficient signal-to-noise-ratio (SNR) and velocity estimation performance. In this paper, broadband coded...... signals are used to increase SNR, followed by subband processing. The received broadband signal is filtered using a set of narrow-band filters. Estimating the velocity in each of the bands and averaging the results yields better performance compared with what would be possible when transmitting a narrow...

  8. Frontiers in optical imaging of cerebral blood flow and metabolism.

    Science.gov (United States)

    Devor, Anna; Sakadžić, Sava; Srinivasan, Vivek J; Yaseen, Mohammad A; Nizar, Krystal; Saisan, Payam A; Tian, Peifang; Dale, Anders M; Vinogradov, Sergei A; Franceschini, Maria Angela; Boas, David A

    2012-07-01

    In vivo optical imaging of cerebral blood flow (CBF) and metabolism did not exist 50 years ago. While point optical fluorescence and absorption measurements of cellular metabolism and hemoglobin concentrations had already been introduced by then, point blood flow measurements appeared only 40 years ago. The advent of digital cameras has significantly advanced two-dimensional optical imaging of neuronal, metabolic, vascular, and hemodynamic signals. More recently, advanced laser sources have enabled a variety of novel three-dimensional high-spatial-resolution imaging approaches. Combined, as we discuss here, these methods are permitting a multifaceted investigation of the local regulation of CBF and metabolism with unprecedented spatial and temporal resolution. Through multimodal combination of these optical techniques with genetic methods of encoding optical reporter and actuator proteins, the future is bright for solving the mysteries of neurometabolic and neurovascular coupling and translating them to clinical utility.

  9. Pulmonary blood flow distribution measured by radionuclide computed tomography

    International Nuclear Information System (INIS)

    Maeda, H.; Itoh, H.; Ishii, Y.

    1982-01-01

    Distributions of pulmonary blood flow per unit lung volume were measured in sitting patients with a radionuclide computed tomography (RCT) by intravenously administered Tc-99m macroaggregates of human serum albumin (MAA). Four different types of distribution were distinguished, among which a group referred as type 2 had a three zonal blood flow distribution as previously reported (West and co-workers, 1964). The pulmonary arterial pressure (Pa) and the venous pressure (Pv) were determined in this group of distribution. These values showed satifactory agreements with the pulmonary artery pressure (Par) and the capillary wedged pressure (Pcw) measured by Swan-Ganz catheter in eighteen supine patients. Those good correlations enable to establish a noninvasive methodology for measurement of pulmonary vascular pressures

  10. Cerebral autoregulation control of blood flow in the brain

    CERN Document Server

    Payne, Stephen

    2016-01-01

    This Brief provides a comprehensive introduction to the control of blood flow in the brain. Beginning with the basic physiology of autoregulation, the author goes on to discuss measurement techniques, mathematical models, methods of analysis, and relevant clinical conditions, all within this single volume. The author draws together this disparate field, and lays the groundwork for future research directions. The text gives an up-to-date review of the state of the art in cerebral autoregulation, which is particularly relevant as cerebral autoregulation moves from the laboratory to the bedside. Cerebral Autoregulation will be useful to researchers in the physical sciences such as mathematical biology, medical physics, and biomedical engineering whose work is concerned with the brain. Researchers in the medical sciences and clinicians dealing with the brain and blood flow, as well as industry professionals developing techniques such as ultrasound, MRI, and CT will also find this Brief of interest.

  11. Ultrasonic Doppler measurement of renal artery blood flow

    Science.gov (United States)

    Freund, W. R.; Meindl, J. D.

    1975-01-01

    An extensive evaluation of the practical and theoretical limitations encountered in the use of totally implantable CW Doppler flowmeters is provided. Theoretical analyses, computer models, in-vitro and in-vivo calibration studies describe the sources and magnitudes of potential errors in the measurement of blood flow through the renal artery, as well as larger vessels in the circulatory system. The evaluation of new flowmeter/transducer systems and their use in physiological investigations is reported.

  12. Computer Simulations of Coronary Blood Flow Through a Constriction

    Science.gov (United States)

    2014-03-01

    for clinical translation. Journal of the American College of Cardiology . 59(15): 1337–1349. Leimgruber, P., Roubin, G., Hollman, J., Cotsonis, G...the artery and increase blood flow. Generally a stent, or a mesh wire tube, is permanently inserted in order to scaffold open the artery wall...central regions of the channel, so the magnitude of the velocity has to be higher in the open area of the channel, overshooting the experimental results

  13. High spatial resolution and high contrast visualization of brain arteries and veins. Impact of blood pool contrast agent and water-selective excitation imaging at 3T

    International Nuclear Information System (INIS)

    Spuentrup, E.; Jacobs, J.E.; Kleimann, J.F.

    2010-01-01

    Purpose: To investigate a blood pool contrast agent and water-selective excitation imaging at 3 T for high spatial and high contrast imaging of brain vessels including the veins. Methods and Results: 48 clinical patients (47 ± 18 years old) were included. Based on clinical findings, twenty-four patients received a single dose of standard extracellular Gadoterate-meglumine (Dotarem registered ) and 24 received the blood pool contrast agent Gadofosveset (Vasovist registered ). After finishing routine MR protocols, all patients were investigated with two high spatial resolution (0.15 mm 3 voxel size) gradient echo sequences in random order in the equilibrium phase (steady-state) as approved by the review board: A standard RF-spoiled gradient-echo sequence (HR-SS, TR/TE 5.1 / 2.3 msec, FA 30 ) and a fat-suppressed gradient-echo sequence with water-selective excitation (HR-FS, 1331 binominal-pulse, TR/TE 8.8 / 3.8 msec, FA 30 ). The images were subjectively assessed (image quality with vessel contrast, artifacts, depiction of lesions) by two investigators and contrast-to-noise ratios (CNR) were compared using the Student's t-test. The image quality and CNR in the HR-FS were significantly superior compared to the HR-SS for both contrast agents (p < 0.05). The CNR was also improved when using the blood pool agent but only to a minor extent while the subjective image quality was similar for both contrast agents. Conclusion: The utilized sequence with water-selective excitation improved image quality and CNR properties in high spatial resolution imaging of brain arteries and veins. The used blood pool contrast agent improved the CNR only to a minor extent over the extracellular contrast agent. (orig.)

  14. Real-time direct measurement of spinal cord blood flow at the site of compression: relationship between blood flow recovery and motor deficiency in spinal cord injury.

    Science.gov (United States)

    Hamamoto, Yuichiro; Ogata, Tadanori; Morino, Tadao; Hino, Masayuki; Yamamoto, Haruyasu

    2007-08-15

    An in vivo study to measure rat spinal cord blood flow in real-time at the site of compression using a newly developed device. To evaluate the change in thoracic spinal cord blood flow by compression force and to clarify the association between blood flow recovery and motor deficiency after a spinal cord compression injury. Until now, no real-time measurement of spinal cord blood flow at the site of compression has been conducted. In addition, it has not been clearly determined whether blood flow recovery is related to motor function after a spinal cord injury. Our blood flow measurement system was a combination of a noncontact type laser Doppler system and a spinal cord compression device. The rat thoracic spinal cord was exposed at the 11th vertebra and spinal cord blood flow at the site of compression was continuously measured before, during, and after the compression. The functioning of the animal's hind-limbs was evaluated by the Basso, Beattie and Bresnahan scoring scale and the frequency of voluntary standing. Histologic changes such as permeability of blood-spinal cord barrier, microglia proliferation, and apoptotic cell death were examined in compressed spinal cord tissue. The spinal blood flow decreased on each increase in the compression force. After applying a 5-g weight, the blood flow decreased to compression), while no significant difference was observed between the 20-minute ischemia group and the sham group. In the 20-minute ischemia group, the rats whose spinal cord blood flow recovery was incomplete showed significant motor function loss compared with rats that completely recovered blood flow. Extensive breakdown of blood-spinal cord barrier integrity and the following microglia proliferation and apoptotic cell death were detected in the 40-minute complete ischemia group. Duration of ischemia/compression and blood flow recovery of the spinal cord are important factors in the recovery of motor function after a spinal cord injury.

  15. Cerebral blood flow and metabolic abnormalities in Alzheimer's disease

    International Nuclear Information System (INIS)

    Matsuda, Hiroshi

    2001-01-01

    In this review I summarize observations of PET and SPECT studies about cerebral blood flow and metabolic abnormalities in Alzheimer's disease (AD). In very early AD flow or metabolism reduces first in the posterior cingulate gyrus and precuneus. This reduction may arise from functional deafferentation caused by primary neural degeneration in the remote area of the entorhinal cortex that is the first to be pathologically affected in AD. Then medial temporal structures and parietotemporal association cortex show flow or metabolic reduction as disease processes. The reason why flow or metabolism in medial temporal structures shows delay in starting to reduce in spite of the earliest pathological affection remains to be elucidated. It is likely that anterior cingulate gyrus is functionally involved, since attention is the first non-memory domain to be affected, before deficits in language and visuospatial functions. However few reports have described involvement in the anterior cingulate gyrus. Relationship between cerebral blood flow or metabolism and apolipoprotein E (APOE) genotype has been investigated. Especially, the APOEε4 allele has been reported to increase risk and to lower onset age as a function of the inherited dose of the ε4 allele. Reduction of flow or metabolism in the posterior cingulate gyrus and precuneus has been reported even in presymptomatic nondemented subjects who were cognitively normal and had at least a single ε4 allele. On the contrary the relation of ε4 allele to the progression rate of AD has been controversial from neuroimaging approaches. PET and SPECT imaging has become to be quite useful for assessing therapeutical effects of newly introduced treatment for AD. Recent investigations observed significant regional flow increase after donepezil hydrochloride treatment. Most of these observations have been made by applying computer assisted analysis of three-dimensional stereotactic surface projection or statistical parametric mapping

  16. Microfluidics to Mimic Blood Flow in Health and Disease

    Science.gov (United States)

    Sebastian, Bernhard; Dittrich, Petra S.

    2018-01-01

    Throughout history, capillary systems have aided the establishment of the fundamental laws of blood flow and its non-Newtonian properties. The advent of microfluidics technology in the 1990s propelled the development of highly integrated lab-on-a-chip platforms that allow highly accurate replication of vascular systems' dimensions, mechanical properties, and biological complexity. Applications include the detection of pathological changes to red blood cells, white blood cells, and platelets at unparalleled sensitivity and the efficacy assessment of drug treatment. Recent efforts have aimed at the development of microfluidics-based tests usable in a clinial environment or the replication of more complex diseases such as thrombosis. These microfluidic disease models enable the study of onset and progression of disease as well as the identification of key players and risk factors, which have led to a spectrum of clinically relevant findings.

  17. Quantitation of cerebral blood flow using HMPAO tomography

    International Nuclear Information System (INIS)

    Bruyant, P.; Mallet, J.J.; Sau, J.; Teyssier, R.; Bonmartin, A.

    1997-01-01

    A method has been developed to quantitate regional cerebral blood flow (rCBF) using 99m Tc-HMPAO. It relies on the application of the bolus distribution principle. The rCBF is determined using compartmental analysis, by measuring the amount of tracer retained in the parenchyma and the input function. The values for blood: brain partition coefficient and for the conversion rate from the lipophilic to the hydrophilic form of the tracer are taken from the literature. Mean values for rCBF in eight patients are 41.1 ± 6.4 et 25.6 ± 5.8 mL.min -1 for the grey matter and for the white matter respectively (mean±standard deviation). This method allows to quantitate rCBF with one SPET scan and one venous blood sample. (authors)

  18. Blood flow distribution with adrenergic and histaminergic antagonists

    Energy Technology Data Exchange (ETDEWEB)

    Baker, C.H.; Davis, D.L.; Sutton, E.T.

    1989-03-01

    Superficial fibular nerve stimulation (SFNS) causes increased pre- and post-capillary resistances as well as increased capillary permeability in the dog hind paw. These responses indicate possible adrenergic and histaminergic interactions. The distribution of blood flow between capillaries and arteriovenous anastomoses (AVA) may depend on the relative effects of these neural inputs. Right hind paws of anesthetized heparinized dogs were vascularly and neurally isolated and perfused with controlled pressure. Blood flow distribution was calculated from the venous recovery of 85Sr-labeled microspheres (15 microns). The mean transit times of 131I-albumin and 85Sr-labeled microspheres were calculated. The effects of adrenergic and histaminergic antagonists with and without SFNS were determined. Phentolamine blocked the entire response to SFNS. Prazosin attenuated increases in total and AVA resistance. Yohimbine prevented increased total resistance, attenuated the AVA resistance increase, and revealed a decrease in capillary circuit resistance. Pyrilamine attenuated total resistance increase while SFNS increased capillary and AVA resistances. Metiamide had no effect on blood flow distribution with SFNS. The increase in AVA resistance with SFNS apparently resulted from a combination of alpha 1 and alpha 2 receptor stimulation but not histaminergic effects.

  19. Blood flow distribution with adrenergic and histaminergic antagonists

    International Nuclear Information System (INIS)

    Baker, C.H.; Davis, D.L.; Sutton, E.T.

    1989-01-01

    Superficial fibular nerve stimulation (SFNS) causes increased pre- and post-capillary resistances as well as increased capillary permeability in the dog hind paw. These responses indicate possible adrenergic and histaminergic interactions. The distribution of blood flow between capillaries and arteriovenous anastomoses (AVA) may depend on the relative effects of these neural inputs. Right hind paws of anesthetized heparinized dogs were vascularly and neurally isolated and perfused with controlled pressure. Blood flow distribution was calculated from the venous recovery of 85Sr-labeled microspheres (15 microns). The mean transit times of 131I-albumin and 85Sr-labeled microspheres were calculated. The effects of adrenergic and histaminergic antagonists with and without SFNS were determined. Phentolamine blocked the entire response to SFNS. Prazosin attenuated increases in total and AVA resistance. Yohimbine prevented increased total resistance, attenuated the AVA resistance increase, and revealed a decrease in capillary circuit resistance. Pyrilamine attenuated total resistance increase while SFNS increased capillary and AVA resistances. Metiamide had no effect on blood flow distribution with SFNS. The increase in AVA resistance with SFNS apparently resulted from a combination of alpha 1 and alpha 2 receptor stimulation but not histaminergic effects

  20. Ocular Blood Flow Measured Noninvasively in Zero Gravity

    Science.gov (United States)

    Ansari, Rafat R.; Manuel, Francis K.; Geiser, Martial; Moret, Fabrice; Messer, Russell K.; King, James F.; Suh, Kwang I.

    2003-01-01

    In spaceflight or a reduced-gravity environment, bodily fluids shift to the upper extremities of the body. The pressure inside the eye, or intraocular pressure, changes significantly. A significant number of astronauts report changes in visual acuity during orbital flight. To date this remains of unknown etiology. Could choroidal engorgement be the primary mechanism and a change in the curvature or shape of the cornea or lens be the secondary mechanism for this change in visual acuity? Perfused blood flow in the dense meshwork of capillaries of the choroidal tissue (see the preceding illustration) provides necessary nutrients to the outer layers of the retina (photoreceptors) to keep it healthy and maintain good vision. Unlike the vascular system, the choroid has no baroreceptors to autoregulate fluid shifts, so it can remain engorged, pushing the macula forward and causing a hyperopic (farsighted) shift of the eye. Experiments by researchers at the NASA Glenn Research Center could help answer this question and facilitate planning for long-duration missions. We are investigating the effects of zero gravity on the choroidal blood flow of volunteer subjects. This pilot project plans to determine if choroidal blood flow is autoregulated in a reduced-gravity environment.

  1. Cerebral blood flow is reduced in patients with sepsis syndrome

    International Nuclear Information System (INIS)

    Bowton, D.L.; Bertels, N.H.; Prough, D.S.; Stump, D.A.

    1989-01-01

    The relationship between sepsis-induced CNS dysfunction and changes in brain blood flow remains unknown, and animal studies examining the influence of sepsis on cerebral blood flow (CBF) do not satisfactorily address that relationship. We measured CBF and cerebrovascular reactivity to CO 2 in nine patients with sepsis syndrome using the 133 Xe clearance technique. Mean CBF was 29.6 +/- 15.8 (SD) ml/100 g.min, significantly lower than the normal age-matched value in this laboratory of 44.9 +/- 6.2 ml/100 g.min (p less than .02). This depression did not correlate with changes in mean arterial pressure. Despite the reduction in CBF, the specific reactivity of the cerebral vasculature to changes in CO 2 was normal, 1.3 +/- 0.9 ml/100 g.min/mm Hg. Brain blood flow is reduced in septic humans; the contribution of this reduction to the metabolic and functional changes observed in sepsis requires further study

  2. Sclerotherapy of Varicose Veins and Spider Veins

    Science.gov (United States)

    ... Index A-Z Sclerotherapy of Varicose Veins and Spider Veins Sclerotherapy uses injections from a very fine, ... Sclerotherapy? What is Sclerotherapy of Varicose Veins and Spider Veins? Sclerotherapy is a minimally invasive treatment used ...

  3. Effect of hematocrit and systolic blood pressure on cerebral blood flow in newborn infants

    International Nuclear Information System (INIS)

    Younkin, D.P.; Reivich, M.; Jaggi, J.L.; Obrist, W.D.; Delivoria-Papadopoulos, M.

    1987-01-01

    The effects of hematocrit and systolic blood pressure on cerebral blood flow were measured in 15 stable, low birth weight babies. CBF was measured with a modification of the xenon-133 ( 133 Xe) clearance technique, which uses an intravenous bolus of 133 Xe, an external chest detector to estimate arterial 133 Xe concentration, eight external cranial detectors to measure cephalic 133 Xe clearance curves, and a two-compartmental analysis of the cephalic 133 Xe clearance curves to estimate CBF. There was a significant inverse correlation between hematocrit and CBF, presumably due to alterations in arterial oxygen content and blood viscosity. Newborn CBF varied independently of systolic blood pressure between 60 and 84 mm Hg, suggesting an intact cerebrovascular autoregulatory mechanism. These results indicate that at least two of the factors that affect newborn animal CBF are operational in human newborns and may have important clinical implications

  4. The effect of blood cell count on coronary flow in patients with coronary slow flow phenomenon.

    Science.gov (United States)

    Soylu, Korhan; Gulel, Okan; Yucel, Huriye; Yuksel, Serkan; Aksan, Gokhan; Soylu, Ayşegül İdil; Demircan, Sabri; Yılmaz, Ozcan; Sahin, Mahmut

    2014-09-01

    The coronary slow flow phenomenon (CSFP) is a coronary artery disease with a benign course, but its pathological mechanisms are not yet fully understood.The purpose of this controlled study was to investigate the cellular content of blood in patients diagnosed with CSFP and the relationship of this with coronary flow rates. Selective coronary angiographies of 3368 patients were analyzed to assess Thrombolysis in Myocardial Infarction (TIMI) frame count (TFC) values. Seventy eight of them had CSFP, and their demographic and laboratory findings were compared with 61 patients with normal coronary flow. Patients' demographic characteristics were similar in both groups. Mean corrected TFC (cTFC) values were significantly elevated in CSFP patients (p<0.001). Furthermore, hematocrit and hemoglobin values, and eosinophil and basophil counts of the CSFP patients were significantly elevated compared to the values obtained in the control group (p=0.005, p=0.047, p=0.001 and p=0.002, respectively). The increase observed in hematocrit and eosinophil levels showed significant correlations with increased TFC values (r=0.288 and r=0.217, respectively). Significant changes have been observed in the cellular composition of blood in patients diagnosed with CSFP as compared to the patients with normal coronary blood flow. The increases in hematocrit levels and in the eosinophil and basophil counts may have direct or indirect effects on the rate of coronary blood flow.

  5. Rotating permanent magnet excitation for blood flow measurement.

    Science.gov (United States)

    Nair, Sarath S; Vinodkumar, V; Sreedevi, V; Nagesh, D S

    2015-11-01

    A compact, portable and improved blood flow measurement system for an extracorporeal circuit having a rotating permanent magnetic excitation scheme is described in this paper. The system consists of a set of permanent magnets rotating near blood or any conductive fluid to create high-intensity alternating magnetic field in it and inducing a sinusoidal varying voltage across the column of fluid. The induced voltage signal is acquired, conditioned and processed to determine its flow rate. Performance analysis shows that a sensitivity of more than 250 mV/lpm can be obtained, which is more than five times higher than conventional flow measurement systems. Choice of rotating permanent magnet instead of an electromagnetic core generates alternate magnetic field of smooth sinusoidal nature which in turn reduces switching and interference noises. These results in reduction in complex electronic circuitry required for processing the signal to a great extent and enable the flow measuring device to be much less costlier, portable and light weight. The signal remains steady even with changes in environmental conditions and has an accuracy of greater than 95%. This paper also describes the construction details of the prototype, the factors affecting sensitivity and detailed performance analysis at various operating conditions.

  6. Cardiac output and regional blood flow following trauma

    International Nuclear Information System (INIS)

    Malik, A.B.; Loegering, D.J.; Saba, T.M.; Kaplan, J.E.

    1978-01-01

    The changes in cardiac output (2), regional blood blow (2r) and regional vascular resistance, and arterial pressure were studied in rats subjected to moderate (LD0) or severe (LD50) traumatic shock. 2 and 2r were determined using microspheres at 15, 60 and 180 min posttrauma. Arterial pressure decreased in both groups at 15 min and recovered by 3 h after sublethal (LD0) trauma, while arterial pressure did not return to control levels after LD50 trauma. 2 decreased in both groups at 15 min and returned to control only in the LD0 trauma group by 3 h. Cerebral, coronary, and hepatic arterial flows and resistances were maintained in both groups. Renal, intestinal, and splenic flows decreased and resistances were maintained in both groups. Renal, intestinal, and splenic flows decreased and resistances increased in both groups by 15 min and returned to control levels by 3 h only in the LD0 trauma group. Total hepatic and hepatic portal flows decreased at 60 min and returned to control levels at 3 h after LD0 trauma, while there was significant depression in these parameters 3 h after LD50 trauma. Therefore, sublethal and severe trauma resulted in early redistribution of flow favoring the coronary, cerebral, and hepatic arterial beds. However, renal, intestinal, splenic, and portal flows remained depressed only in severely traumatized rats, suggesting that continued hypofusion is a factor in the multiple organ failure and death following severe traumatic injury

  7. Renal blood flow and metabolism after cold ischaemia

    DEFF Research Database (Denmark)

    Henriksen, J H; Petersen, H K

    1984-01-01

    Peroperative measurements of renal blood flow (RBF), renal O2-uptake, and renal venous lactate/pyruvate (L/P) ratio were performed before and after a period of 30-71 min of hypothermic (10-15 degrees C) renal ischaemia in nine patients, undergoing surgery for renal calculi. Before ischaemia, RBF.......01) immediately after re-established perfusion and 36% (P less than 0.02) 30 min later. In one additional patient, who had a short warm ischaemia (8 min), the flow pattern was the same. As arterial pressure remained constant, the reduced RBF signifies an increased renal vascular resistance. Renal O2-uptake...... and renal venous L/P ratio were almost constant, indicating no significant anaerobic processes being involved in the flow response. None of the patients showed any signs of reactive hyperaemia. It is concluded that hypothermic renal ischaemia may be followed by an increased renal vascular resistance even...

  8. Comparison of blood flow and cell function in ischemic skin flaps

    International Nuclear Information System (INIS)

    Bean, D.; Rees, R.S.; O'Leary, J.P.; Lynch, J.B.

    1984-01-01

    Cellular function and blood flow in acute, steroid-treated, and surgically delayed random skin flaps have been examined. In these studies, the period following flap elevation could be divided into early (0-2 hr), intermediate (4-6 hr), and late (12 hr) periods of ischemia, based on the cutaneous blood flow and cellular function measured by thallium-201 uptake. There was a close correlation between blood flow and cellular function during the early period of ischemia which became worse with time. Blood flow studies demonstrated a significant difference between the early and intermediate periods of ischemia which was abolished by surgical delay. Improvement in cellular function was accomplished by improved blood flow in the surgically delayed flaps, while steroid-treated flaps enhanced cellular metabolism by another mechanism. Cellular function approximated blood flow during the early and immediate period of ischemia. Steroids may augment cellular function without improving blood flow, while surgical delay improves cellular function by improving blood flow

  9. The study of 1H-MRS on monkey of resuscitation after cerebral selection ultra-profound hypothermic blood flow occlusion

    International Nuclear Information System (INIS)

    Pu Jun; Xu Wei; Fang Shaolong; Zhao Xinxiang; Feng Zhongtang; Jiang Jiyao

    2005-01-01

    Objective: To investigate the appearance and feature of 1 H/protion magnetic resonance spectroscopy ( 1 H-MRS) on resuscitation after cerebral selective ultra-profound hypothermic and blood flow occlusion. To study effects of cerebral biochemical metabolism after cerebral selective ultra-profound hypothermia and blood flow occlusion and to explore the validity and feasibility of it. Methods: Bilateral carotid arteries and jugular veins were clipped about 10 minutes before perfusion. Then selective cerebral circulation was established by perfusion of cooling lingers liquid through right internal carotid artery and flow out of left jugular vein with clip of other carotid arteries and jugular veins. Brain temperature reached (15.1 ± 0.9) degree C, while the body temperature maintained (32.50 ± 0.58) degree C. Cerebral blood recovered after 60 minutes of cerebral ischemia and monkey came back. The cerebral MAI and DWI as well as 1 H-MRS were examined 4, 24, 72 h, 21 days before and after cerebral selective ultro-profound hypothermia and blood flow occlusion. The peak of N-acetyl-aspartate (NAA), Choline (Cho), creatine and phosphocreatine (Cr, PCr) of VOL were compare with those of control group in different time. Results: MRI T 1 WI, MRI T 2 WI and DWI is normal in different time in different region; there was not a significant difference in the ratio of NAA/(Cr+PCr), Cho/(Cr+PCr) in ROI in different time in the different region in the light of statistical analysis (P>0.05). Conclusion: The light of cerebral biochemical metabolism, selective ultra-profound hypothermia is safety and may provide effective protective effects and safety during cerebral ischemia. (authors)

  10. Cerebral blood flow and cerebrovascular response to acetazolamide in patients with chronic alcoholism

    OpenAIRE

    Oishi, M; Mochizuki, Y; Takasu, T

    1997-01-01

    Cerebral blood flow and cerebrovascular response to acetazolamide were studied in 12 patients with chronic alcoholism and 12 age matched healthy controls. Blood flows in the cerebral cortex, thalamus, and putamen were significantly lower in the chronic alcoholic group than in the healthy control group. The increase in blood flow caused by acetazolamide did not show any significant difference between the two groups. These findings suggest that the decreased cerebral blood flow i...

  11. Resistance exercise with different volumes: blood pressure response and forearm blood flow in the hypertensive elderly

    Directory of Open Access Journals (Sweden)

    Brito AF

    2014-12-01

    Full Text Available Aline de Freitas Brito,1 Caio Victor Coutinho de Oliveira,2 Maria do Socorro Brasileiro-Santos,1 Amilton da Cruz Santos1 1Physical Education Department, 2Research Laboratory for Physical Training Applied to Performance and Health, Federal University of Paraíba, João Pessoa, Brazil Background: The purpose of this study was to evaluate the effect of two sessions of resistance exercise with different volumes on post-exercise hypotension, forearm blood flow, and forearm vascular resistance in hypertensive elderly subjects.Methods: The study was conducted with ten hypertensive elderly (65±3 years, 28.7±3 kg/m2 subjected to three experimental sessions, ie, a control session, exercise with a set (S1, and exercise with three sets (S3. For each session, the subjects were evaluated before and after intervention. In the pre-intervention period, blood pressure, forearm blood flow, and forearm vascular resistance were measured after 10 minutes of rest in the supine position. Thereafter, the subjects were taken to the gym to perform their exercise sessions or remained at rest during the same time period. Both S1 and S3 comprised a set of ten repetitions of ten exercises, with an interval of 90 seconds between exercises. Subsequently, the measurements were again performed at 10, 30, 50, 70, and 90 minutes of recovery (post-intervention in the supine position.Results: Post-exercise hypotension was greater in S3 than in S1 (systolic blood pressure, −26.5±4.2 mmHg versus −17.9±4.7 mmHg; diastolic blood pressure, −13.8±4.9 mmHg versus −7.7±5 mmHg, P<0.05. Similarly, forearm blood flow and forearm vascular resistance changed significantly in both sessions with an increase and decrease, respectively, that was more evident in S3 than in S1 (P<0.05.Conclusion: Resistance exercises with higher volume were more effective in causing post-exercise hypotension, being accompanied by an increase in forearm blood flow and a reduction of forearm vascular

  12. Effect of strict metabolic control on regulation of subcutaneous blood flow in insulin-dependent diabetic patients

    DEFF Research Database (Denmark)

    Kastrup, J; Mathiesen, E R; Saurbrey, Nina

    1987-01-01

    washout technique. Mean arterial blood pressure was reduced by a maximum of 23 mmHg by elevating the limb above heart level and elevated to a maximum of 65 mmHg by head-up tilt; in the latter position venous pressure was kept constantly low by activation of the leg muscle vein pump (heel raising......The effect of 10 weeks of improved metabolic control on the impaired autoregulation of the subcutaneous blood flow was studied at the level of the lateral malleolus in eight long-term insulin-dependent diabetic patients with clinical microangiopathy. Blood flow was measured by the local 133-Xenon......). Improved metabolic control was achieved using either continuous subcutaneous insulin infusion or multiple insulin injections. The blood glucose concentration declined from (median) 12.7 to 6.8 mmol/l and the HbA1C level from 10.1 to 7.5% during strict metabolic control (p less than 0.01 and p less than 0...

  13. C-14-activity incorporation into the protein of fetal organs of guinea pigs with different maternal placental blood flow and fetal arterial O2-saturation

    International Nuclear Information System (INIS)

    Duenzl, B.

    1981-01-01

    In anaesthesised gravid guinea-pigs the dilate, end section of a placental radial artery was connected to the A.carotis via a flow meter and a throttle in order to measure and widely alter the maternal placental blood flow. Blood samples are taken from the fetal A.carotis, the fetal arterial O 2 -saturation and the Hb-content were determined. By altering the maternal placental blood circulation the fetal arterial O 2 -concentration can stabilised at various levels. In order to study the protein synthesis, under these conditions one infused 185 kBq C-14-leucine over a period of 3 hours into the jugular vein of the fetus. During infusion the radioactive concentrations in whole plasma and plasma water were measured. After the infusion the radioactive concentrations in the tissue fluid, the intracellular fluid and the acid-insoluble tissue fraction (protein) of the heart, kidenys, liver, the muscles of the upper end lower part of the body, the brain and the placenta were measured. The following deductions were drawn from the findings: The maternal placental blood flow vitally influences the activity incorporation per activity concentration in the plasma water. These findings agree with the hypotheses that the maternal blood circulation has an essential influence on the fetal proteins synthesis and that this influence can be attributed to the connection between placenta connection blood flow and oxygen saturation of fetal arterial blood. (orig.) [de

  14. Protection of spermatogenisis during X-irradiation and chemotherapy by temporary blood flow interruption

    International Nuclear Information System (INIS)

    Vliet, J. van.

    1989-01-01

    In an animal model the possibility was tested to interrupt the blood flow to the testis temporarily and repeatedly. Subsequently, it was investigated whether blood flow interuption during irradiation or during cytostatic drug administration could limit the damage induced to the spermatogonial stem cells. The effect of repeatedly blood flow interruptions on spermatogenesis was evaluated. (author). 192 refs.; 15 figs.; 11 tabs

  15. Rhabdomyolysis After Performing Blood Flow Restriction Training: A Case Report.

    Science.gov (United States)

    Tabata, Shogo; Suzuki, Yukio; Azuma, Koichiro; Matsumoto, Hideo

    2016-07-01

    Tabata, S, Suzuki, Y, Azuma, K, and Matsumoto, H. Rhabdomyolysis after performing blood flow restriction training: a case report. J Strength Cond Res 30(7): 2064-2068, 2016-Rhabdomyolysis is a serious and potentially life-threatening condition related to resistance training. Despite numerous reports of low-intensity blood flow restriction (BFR) training inducing muscle hypertrophy and increasing strength, few reports of rhabdomyolysis related to BFR training have been published. Here, we report a 30-year-old obese Japanese man admitted to our hospital the day after his first BFR training session with complaints of severe muscle pain in his upper and lower extremities, high fever, and pharyngeal pain. He was diagnosed with acute rhabdomyolysis based on a serum creatine phosphokinase level of 56,475 U·L and a urine myoglobin level of >3,000 ng·ml, and with acute tonsillitis based on a white blood cell count of 17,390 and C-reactive protein level of 10.43 mg·dl. A number of factors are suspected to be related to the onset and exacerbation of rhabdomyolysis, including excessive muscular training with BFR, bacterial infection, and medication. After 10 days of hospitalization with intravenous fluids and antibacterial drugs, he recovered without complications. This case indicates that BFR training should be conducted with careful consideration of the physical condition and strength of the individual to prevent serious complications, such as rhabdomyolysis.

  16. Tracking flow of leukocytes in blood for drug analysis

    Science.gov (United States)

    Basharat, Arslan; Turner, Wesley; Stephens, Gillian; Badillo, Benjamin; Lumpkin, Rick; Andre, Patrick; Perera, Amitha

    2011-03-01

    Modern microscopy techniques allow imaging of circulating blood components under vascular flow conditions. The resulting video sequences provide unique insights into the behavior of blood cells within the vasculature and can be used as a method to monitor and quantitate the recruitment of inflammatory cells at sites of vascular injury/ inflammation and potentially serve as a pharmacodynamic biomarker, helping screen new therapies and individualize dose and combinations of drugs. However, manual analysis of these video sequences is intractable, requiring hours per 400 second video clip. In this paper, we present an automated technique to analyze the behavior and recruitment of human leukocytes in whole blood under physiological conditions of shear through a simple multi-channel fluorescence microscope in real-time. This technique detects and tracks the recruitment of leukocytes to a bioactive surface coated on a flow chamber. Rolling cells (cells which partially bind to the bioactive matrix) are detected counted, and have their velocity measured and graphed. The challenges here include: high cell density, appearance similarity, and low (1Hz) frame rate. Our approach performs frame differencing based motion segmentation, track initialization and online tracking of individual leukocytes.

  17. Association between exercise intensity and renal blood flow evaluated using ultrasound echo.

    Science.gov (United States)

    Kawakami, Shotaro; Yasuno, Tetsuhiko; Matsuda, Takuro; Fujimi, Kanta; Ito, Ai; Yoshimura, Saki; Uehara, Yoshinari; Tanaka, Hiroaki; Saito, Takao; Higaki, Yasuki

    2018-03-10

    High-intensity exercise reduces renal blood flow (RBF) and may transiently exacerbate renal dysfunction. RBF has previously been measured invasively by administration of an indicator material; however, non-invasive measurement is now possible with technological innovations. This study examined variations in RBF at different exercise intensities using ultrasound echo. Eight healthy men with normal renal function (eGFR cys 114 ± 19 mL/min/1.73 m 2 ) participated in this study. Using a bicycle ergometer, participants underwent an incremental exercise test using a ramp protocol (20 W/min) until exhaustion in Study 1 and the lactate acid breaking point (LaBP) was calculated. Participants underwent a multi-stage test at exercise intensities of 60, 80, 100, 120, and 140% LaBP in Study 2. RBF was measured by ultrasound echo at rest and 5 min after exercise in Study 1 and at rest and immediately after each exercise in Study 2. To determine the mechanisms behind RBF decline, a catheter was placed into the antecubital vein to study vasoconstriction dynamics. RBF after maximum exercise decreased by 51% in Study 1. In Study 2, RBF showed no significant decrease until 80% LaBP, and showed a significant decrease (31%) at 100% LaBP compared with at rest (p blood lactate. Reduction in RBF with exercise above the intensity at LaBP was due to decreased cross-sectional area rather than time-averaged flow velocity.

  18. Brain blood flow and blood pressure during hypoxia in the epaulette shark Hemiscyllium ocellatum, a hypoxia-tolerant elasmobranch.

    Science.gov (United States)

    Söderström, V; Renshaw, G M; Nilsson, G E

    1999-04-01

    The key to surviving hypoxia is to protect the brain from energy depletion. The epaulette shark (Hemiscyllium ocellatum) is an elasmobranch able to resist energy depletion and to survive hypoxia. Using epi-illumination microscopy in vivo to observe cerebral blood flow velocity on the brain surface, we show that cerebral blood flow in the epaulette shark is unaffected by 2 h of severe hypoxia (0.35 mg O2 l-1 in the respiratory water, 24 C). Thus, the epaulette shark differs from other hypoxia- and anoxia-tolerant species studied: there is no adenosine-mediated increase in cerebral blood flow such as that occurring in freshwater turtles and cyprinid fish. However, blood pressure showed a 50 % decrease in the epaulette shark during hypoxia, indicating that a compensatory cerebral vasodilatation occurs to maintain cerebral blood flow. We observed an increase in cerebral blood flow velocity when superfusing the normoxic brain with adenosine (making sharks the oldest vertebrate group in which this mechanism has been found). The adenosine-induced increase in cerebral blood flow velocity was reduced by the adenosine receptor antagonist aminophylline. Aminophylline had no effect upon the maintenance of cerebral blood flow during hypoxia, however, indicating that adenosine is not involved in maintaining cerebral blood flow in the epaulette shark during hypoxic hypotension.

  19. Laser Doppler flowmetry for bone blood flow measurement: correlation with microsphere estimates and evaluation of the effect of intracapsular pressure on femoral head blood flow

    International Nuclear Information System (INIS)

    Swiontkowski, M.F.; Tepic, S.; Perren, S.M.; Moor, R.; Ganz, R.; Rahn, B.A.

    1986-01-01

    Laser Doppler flowmetry (LDF) was used to measure bone blood flow in the rabbit femoral condyles. To correlate the LDF output signal blood cell flux to in vivo blood flow, simultaneous measurements using LDF and 85 Sr-labeled microspheres were made in an adult rabbit model. There was no correlation between the two methods for blood flow in the femoral condyles and the correlation between the two methods for blood flow in the femoral head does not achieve statistical significance. An LDF signal of 0.4 V was approximately equal to a microsphere measured flow rate of 0.4 ml blood/g bone/min. The strength of the correlation in the latter case may have been affected by (a) large arteriovenous shunts, (b) inadequate mixing of the microspheres with a left ventricular injection, and (c) insufficient numbers of microspheres present in the bone samples. When LDF was used to evaluate the effect of elevated intracapsular pressure on femoral head blood flow in skeletally mature rabbits, femoral head subchondral bone blood flow declined with increasing intracapsular pressure from a baseline value of 0.343 +/- 0.036 to a value of 0.127 +/- 0.27 at 120 cm of water pressure. The decline in femoral head blood flow was statistically significant at pressures of 40 cm of water or higher (p less than 0.001), and evaluation of sections of the proximal femora made from preterminal disulphine blue injections confirmed these findings. Intracapsular tamponade has an adverse effect on femoral head blood flow beginning well below central venous pressure and should be considered in the pathophysiology of posttraumatic and nontraumatic necrosis of the femoral head. Laser Doppler flowmetry was easy to use and appears to be a reproducible technique for evaluating femoral head blood flow, offering distinct advantages over the microsphere technique for measuring bone blood flow

  20. Complex blood flow quantification using real-time in vivo vector flow ultrasound

    DEFF Research Database (Denmark)

    Pedersen, Mads Møller; Pihl, Michael Johannes; Per, Haugaard

    A new method to define and quantify complex blood flow is presented. The standard deviations of real-time in vivo vector flow angle estimates are used. Using vector flow ultrasound imaging both carotid bifurcations of two healthy volunteers were scanned. Scanning was performed with a 7.6 MHz linear...... transducer (8670, B-K Medical, Denmark) and a commercial vector flow ultrasound scanner (ProFocus 2202, B-K Medical). Eight video sequences of one cardiac cycle were obtained. In every frame boxes were placed to define the common carotid artery(box1) and the carotid bulb(box2). The standard deviation...... for the vector angle estimates was calculated for each box in every frame. For comparison three ultrasound experts evaluated the presence of complex flow in every box. The trial was blinded. For every sequence the mean standard deviation of the vector angle estimates were calculated for box1 {39...

  1. Blood pressure and blood flow variation during postural change from sitting to standing: model development and validation

    DEFF Research Database (Denmark)

    Olufsen, M.S.; Ottesen, Johnny T.; Tran, H.T.

    2005-01-01

    Short-term cardiovascular responses to postural change from sitting to standing involve complex interactions between the autonomic nervous system, which regulates blood pressure, and cerebral autoregulation, which maintains cerebral perfusion. We present a mathematical model that can predict...... dynamic changes in beat-to-beat arterial blood pressure and middle cerebral artery blood flow velocity during postural change from sitting to standing. Our cardiovascular model utilizes 11 compartments to describe blood pressure, blood flow, compliance, and resistance in the heart and systemic circulation....... To include dynamics due to the pulsatile nature of blood pressure and blood flow, resistances in the large systemic arteries are modeled using nonlinear functions of pressure. A physiologically based submodel is used to describe effects of gravity on venous blood pooling during postural change. Two types...

  2. Alteration of pulmonary blood flow in tetralogy of Fallot

    International Nuclear Information System (INIS)

    Hashimoto, Kazuhiro; Matsui, Michihiko; Kurosawa, Hiromi; Arai, Tatsuta; Nakamura, Yuzuru.

    1992-01-01

    The pulmonary blood distribution was examined in 17 patients with tetralogy of Fallot (TOF) pre and postoperatively with macroaggregates of 99m TC-labeled human serum albumin. Most of the patients with TOF demonstrated an abnormal preoperative distribution pattern. The abnormalities included not only an unbalanced distribution between the right and left lungs but also a maldistribution of peripheral vessels in each lung. The right/left lung counts ratio and pulmonary peripheral index (calculated in order to express the severity of peripheral maldistribution) correlated neither to the diameter nor the cross-sectional area of either right or left pulmonary arteries which were measured angiographically. Postoperatively, the pulmonary blood was shunted toward the developed side of the lung which further contributed to maldistribution of blood flow and unbalanced pulmonary growth. Since the patients with an unbalanced pulmonary blood distribution demonstrated a higher right ventricular pressure one year after the operation, a palliative operation facilitating the growth of the underdeveloped side of the lung might be considered as an effective procedure to precede intracardiac repair. (author)

  3. Modelling of impaired cerebral blood flow due to gaseous emboli

    International Nuclear Information System (INIS)

    Hague, J P; Banahan, C; Chung, E M L

    2013-01-01

    Bubbles introduced to the arterial circulation during invasive medical procedures can have devastating consequences for brain function but their effects are currently difficult to quantify. Here we present a Monte Carlo simulation investigating the impact of gas bubbles on cerebral blood flow. For the first time, this model includes realistic adhesion forces, bubble deformation, fluid dynamical considerations, and bubble dissolution. This allows investigation of the effects of buoyancy, solubility, and blood pressure on embolus clearance. Our results illustrate that blockages depend on several factors, including the number and size distribution of incident emboli, dissolution time and blood pressure. We found it essential to model the deformation of bubbles to avoid overestimation of arterial obstruction. Incorporation of buoyancy effects within our model slightly reduced the overall level of obstruction but did not decrease embolus clearance times. We found that higher blood pressures generate lower levels of obstruction and improve embolus clearance. Finally, we demonstrate the effects of gas solubility and discuss potential clinical applications of the model. (paper)

  4. Role of cerebral blood flow in extreme breath holding.

    Science.gov (United States)

    Bain, Anthony R; Ainslie, Philip N; Hoiland, Ryan L; Willie, Chris K; MacLeod, David B; Madden, Dennis; Maslov, Petra Zubin; Drviš, Ivan; Dujić, Željko

    2016-01-01

    The role of cerebral blood flow (CBF) on a maximal breath-hold (BH) in ultra-elite divers was examined. Divers (n = 7) performed one control BH, and one BH following oral administration of the non-selective cyclooxygenase inhibitor indomethacin (1.2 mg/kg). Arterial blood gases and CBF were measured prior to (baseline), and at BH termination. Compared to control, indomethacin reduced baseline CBF and cerebral delivery of oxygen (CDO 2 ) by about 26% (p tension was higher following oral administration of indomethacin compared to control (4.05 ± 0.45 vs. 3.44 ± 0.32 kPa). The absolute increase in CBF from baseline to the termination of apnea was lower with indomethacin (p = 0.01). These findings indicate that the impact of CBF on maximal BH time is likely attributable to its influence on cerebral H + washout, and therefore central chemoreceptive drive to breathe, rather than to CDO 2 .

  5. Vasodilator interactions in skeletal muscle blood flow regulation

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Nyberg, Michael Permin; Jensen, Lasse Gliemann

    2012-01-01

    During exercise, oxygen delivery to skeletal muscle is elevated to meet the increased oxygen demand. The increase in blood flow to skeletal muscle is achieved by vasodilators formed locally in the muscle tissue, either on the intraluminal or the extraluminal side of the blood vessels. A number...... vasodilators are both stimulated by several compounds, eg. adenosine, ATP, acetylcholine, bradykinin, and are affected by mechanically induced signals, such as shear stress. NO and prostacyclin have also been shown to interact in a redundant manner where one system can take over when formation of the other...... is compromised. Although numerous studies have examined the role of single and multiple pharmacological inhibition of different vasodilator systems, and important vasodilators and interactions have been identified, a large part of the exercise hyperemic response remains unexplained. It is plausible...

  6. Sympathetic reflex control of blood flow in human peripheral tissues

    DEFF Research Database (Denmark)

    Henriksen, O

    1991-01-01

    Sympathetic vasoconstrictor reflexes are essential for the maintenance of arterial blood pressure in upright position. It has been generally believed that supraspinal sympathetic vasoconstrictor reflexes elicited by changes in baroreceptor activity play an important role. Recent studies on human...... sympathetic vasoconstrictor reflexes are blocked. Blood flow has been measure by the local 133Xe-technique. The results indicate the presence of spinal as well as supraspinal sympathetic vasoconstrictor reflexes to human peripheral tissues. Especially is emphasized the presence of a local sympathetic veno...... skeletal muscle, cutaneous and subcutaneous tissues of the limbs indicate that the situation is more complex. Measurements have been carried out during acute as well as chronic sympathetic denervation. Spinal sympathetic reflex mechanisms have been evaluated in tetraplegic patients, where supraspinal...

  7. Prioritizing blood flow: cardiovascular performance in response to the competing demands of locomotion and digestion for the Burmese python, Python molurus.

    Science.gov (United States)

    Secor, Stephen M; White, Scott E

    2010-01-01

    Individually, the metabolic demands of digestion or movement can be fully supported by elevations in cardiovascular performance, but when occurring simultaneously, vascular perfusion may have to be prioritized to either the gut or skeletal muscles. Burmese pythons (Python molurus) experience similar increases in metabolic rate during the digestion of a meal as they do while crawling, hence each would have an equal demand for vascular supply when these two actions are combined. To determine, for the Burmese python, whether blood flow is prioritized when snakes are digesting and moving, we examined changes in cardiac performance and blood flow in response to digestion, movement, and the combination of digestion and movement. We used perivascular blood flow probes to measure blood flow through the left carotid artery, dorsal aorta, superior mesenteric artery and hepatic portal vein, and to calculate cardiac output, heart rate and stroke volume. Fasted pythons while crawling experienced a 2.7- and 3.3-fold increase, respectively, in heart rate and cardiac output, and a 66% decrease in superior mesenteric flow. During the digestion of a rodent meal equaling in mass to 24.7% of the snake's body mass, heart rate and cardiac output increased by 3.3- and 4.4-fold, respectively. Digestion also resulted in respective 11.6- and 14.1-fold increases in superior mesenteric and hepatic portal flow. When crawling while digesting, cardiac output and dorsal aorta flow increased by only 21% and 9%, respectively, a modest increase compared with that when they start to crawl on an empty stomach. Crawling did triggered a significant reduction in blood flow to the digesting gut, decreasing superior mesenteric and hepatic portal flow by 81% and 47%, respectively. When faced with the dual demands of digestion and crawling, Burmese pythons prioritize blood flow, apparently diverting visceral supply to the axial muscles.

  8. Cerebral blood flow and metabolism during controlled hypotension with sodium-nitroprusside and general anaesthesia for total hip replacement a.m. Charnley

    International Nuclear Information System (INIS)

    Buenemann, L.; Jensen, K.; Thomsen, L.; Riisager, S.

    1987-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRo 2 ) were studied during hypotension induced with sodium nitroprusside (SNP) in 10 patients undergoing total hip replacement a.m. Charnley. Cerebral blood flow was measured using an injection of xenon-133 into an arm vein. The decay curve was detected by five scintillation counters placed over each hemisphere and analysed with the Novo 10a cerebrograph. Blood samples were drawn from the radial artery and the jugular venous bulb to calculate the CMRo 2 . In the gropu as a whole, there were significant decreases in mean arterial pressure and in cerebrovascular resistance. There were no significant changes, in either CBF or CMRo 2 in the gropu as a whole, but there were substantial individual differences. In conclusion, the use of SNP-induced hypotension for extracranial surgery should be used only in patients monitored closely. (author)

  9. Metabolic control of muscle blood flow during exercise in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher

    2003-01-01

    that combined blockade of NOS and PGI2, and NOS and cytochrome P450, both attenuate exercise-induced hyperemia in humans. Combined vasodilator blockade studies offer the potential to uncover important interactions and compensatory vasodilator responses. The signaling pathways that link metabolic events evoked...... to exert control of muscle vasodilation. Adenosine, nitric oxide (NO), prostacyclin (PGI2), and endothelial-derived hyperpolarization factor (EDHF) are possible mediators of muscle vasodilation during exercise. In humans, adenosine has been shown to contribute to functional hyperemia as blood flow...... by muscle contraction to vasodilatory signals in the local vascular bed remains an important area of study....

  10. Oscillations and chaos in renal blood flow control

    DEFF Research Database (Denmark)

    Holstein-Rathlou, N H

    1993-01-01

    In normotensive, halothane-anesthetized rats, oscillations can be found both in the single-nephron blood flow and in the tubular pressure. Experimental data and computer simulations support the hypothesis that the oscillations are caused by the tubuloglomerular feedback (TGF) mechanism. Model...... oscillations. The parameter range where model studies show instability overlaps with the physiologic range for the values of the same parameters. The system appears to be poised on the border between stability and oscillation, and a small parameter change may cause the system to move from one state...

  11. Regional cerebral blood flow in psychiatry: Application to clinical research

    International Nuclear Information System (INIS)

    Berman, K.F.; Weinberger, D.R.; Morihisa, J.M.; Zec, R.F.

    1984-01-01

    In the following sections, the authors describe aspects of the xenon-133 inhalation technique as it has been modified in their lab, as well as a number of considerations and prerequisites for setting up such a facility. The authors also discuss the processes by which they technically and clinically validated the methods used. Several case studies follow along with descriptions of the approaches they are taking in investigating psychiatric illnesses with rCBF. Since the concept of a relation between brain functional activity, metabolism, and blood flow has a long history, both in theory and in practice, they first briefly review some of this history and some of the principles involved

  12. Brain energy metabolism and blood flow differences in healthy aging

    DEFF Research Database (Denmark)

    Aanerud, Joel; Borghammer, Per; Chakravarty, M Mallar

    2012-01-01

    Cerebral metabolic rate of oxygen consumption (CMRO(2)), cerebral blood flow (CBF), and oxygen extraction fraction (OEF) are important indices of healthy aging of the brain. Although a frequent topic of study, changes of CBF and CMRO(2) during normal aging are still controversial, as some authors......, and in the temporal cortex. Because of the inverse relation between OEF and capillary oxygen tension, increased OEF can compromise oxygen delivery to neurons, with possible perturbation of energy turnover. The results establish a possible mechanism of progression from healthy to unhealthy brain aging, as the regions...

  13. Cerebral blood flow measurement techniques in infants and children

    International Nuclear Information System (INIS)

    Kirsch, J.R.; Traystman, R.J.; Rogers, M.C.

    1985-01-01

    The tremendous growth of interest in neurologic intensive care and in the pathophysiology of the cerebral circulation in the past few years has resulted in increasing numbers of studies that document alterations in cerebral flow during the course of various diseases or as a response to treatment of them. Before pediatricians come to conclusions based on these studies, it is important to have an understanding of the techniques involved. The techniques are complex and difficult but are based on understandable principles. They also have limitations and are subject to misinterpretations. Pediatricians should become knowledgeable about some of these techniques and their limitations because it is likely that they will be applied with increasing frequency in the next several years. We are on the threshold of exciting discoveries in abnormalities of cerebral blood flow and cerebral metabolism not only in critically ill children but also in children with congenital and learning disorders

  14. Quantitative assessment of cerebral blood flow by 123I-IMP SPECT

    International Nuclear Information System (INIS)

    Moriwaki, Hiroshi; Matsumoto, Masayasu; Hashikawa, Kazuo

    1993-01-01

    To establish a noninvasive, quantitative method for measuring regional cerebral blood flow (rCBF) by N-isopropyl-p-[ 123 I]iodoamphetamine ( 123 I-IMP) SPECT, we attempted to employ continuous venous sampling instead of arterial sampling. Forty two patients with cerebrovascular disease were classified into two groups, with (group II: n=35) and without (group I: n=7) hand warming. In group II, either hand was warmed, wrapping in a hot blanket (group IIA) or immersed in a 44degC water bath (group IIB). Immediately after intravenous bolus injection of 222 MBq IMP, arterial and venous blood samples were collected continuously for 5 min from the radial artery and the cubital vein, respectively. By octanol extraction, IMP was divided into the unmetabolized and metabolized fractions. The ratio of 123 I-IMP of venous blood to arterial blood (pass ratio, referred to as %PR) was calculated in the whole blood, unmetabolized, and metabolized fractions. Using these parameters, we assessed the possibility to estimate the amount of unmetabolized IMP fraction of arterial blood, usually used as an input function, from venous samples. In group I, %PR demonstrated a considerable variation between individuals (whole IMP, 47.5±24.6%; unmetabolized IMP, 46.0±24.5%; metabolized IMP, 51.8±27.4%). In group II, especially in group IIB, both increase of %PR value and the decrease in variation (whole, 77.9±5.6%; unmetabolized, 75.7±5.7%; metabolized, 86.7±8.7%) were observed, permitting the further calculation based on the assumption that %PR value was constant in each IMP fraction. The coefficient of variation of the difference between estimated arterial IMP radioactivity from venous samples and actual arterial IMP was 9.0% and 7.5%. The use of venous sampling coupled with a hand warming technique allowed the estimation of the arterial unmetabolized IMP radioactivity from venous samples with a reliability of 90% or more. (author)

  15. Cerebral blood flow and oxygen metabolism after subarachnoid hemorrhage

    International Nuclear Information System (INIS)

    Ito, Hidemichi; Sakurai, Takashi; Hayashi, Tatsuo; Hashimoto, Takuo

    2004-01-01

    The mechanism of reduction of cerebral circulation in the early phase of aneurysmal subarachnoid hemorrhage (SAH) has not yet been clarified. Previous studies have variously indicated that cerebral blood flow (CBF) reduction may be due to cerebral vasospasm, an elevation in intracranial pressure (ICP), constriction of intraparenchymal arterioles, or metabolic reduction. The aim of this study is to investigate the relationship between cerebral circulation and oxygen metabolism. In 36 patients with aneurysmal SAH, the values of mean cerebral blood flow (mCBF), cerebral metabolic rate of oxygen (GMRO 2 ) and oxygen extraction fraction (OEF) were measured by using single photon emission computed tomography (SPECT) with arterial blood drawing and oxygen saturation of internal jugular bulb blood (SjO 2 ) in the acute stage (1-3 days after onset) and the spasm stage (7-10 days after onset). The patients in our study were selected by using the following criteria: no history of cerebrovascular or cardiopulmonary diseases; under the age of 70; the ruptured aneurysm was treated by clipping or coil embolization within 72 hours after onset; no symptoms of cerebral vasospasm; no signs of cerebral ischemic change on CT scans. These patients were divided into 2 groups according to the World Federation of Neurological Surgeons (WFNS) grading classification; the mild group (Grades I and II) consisted of 27 cases and the severe group (Grade IV) consisted of 9 cases. We studied differences in mCBF CMRO 2 , and OEF between the mild group and severe group. In the mild group, mCBF, CMRO 2 , and OEF were significantly higher than in the severe group during both the acute and the spasm stage. Also mCBF showed a direct correlation with CMRO 2 . All the patients were kept under the following conditions: the bed was positioned so that the upper body was raised at an angle at 30 deg; blood pressure was maintained at 130-150 mmHg and PaCO 2 of arterial blood was maintained at 35-40 mmHg; ICP

  16. Endovascular vein harvest: systemic carbon dioxide absorption.

    Science.gov (United States)

    Maslow, Andrew M; Schwartz, Carl S; Bert, Arthur; Hurlburt, Peter; Gough, Jeffrey; Stearns, Gary; Singh, Arun K

    2006-06-01

    Endovascular vein harvest (EDVH) requires CO(2) insufflation to expand the subcutaneous space, allowing visualization and dissection of the saphenous vein. The purpose of this study was to assess the extent of CO(2) absorption during EDVH. Prospective observational study. Single tertiary care hospital. Sixty patients (30 EDVH and 30 open-vein harvest) undergoing isolated coronary artery bypass graft surgery. Hemodynamic, procedural, and laboratory data were collected prior to (baseline), during, and at it the conclusion (final) of vein harvesting. Data were also collected during cardiopulmonary bypass (CPB). Data were compared by using t tests, analysis of variance, and correlation statistics when needed. There were significant increases in arterial CO(2) (PaCO(2), 35%) and decreases in pH (1.35%) during EDVH. These were associated with increases in heart rate, mean blood pressure, and cardiac output. Within the EDVH group, greater elevations (>10 mmHg) in PaCO2 were more likely during difficult harvest procedures, and these patients exhibited greater increase in heart rate. Elevated CO(2) persisted during CPB, requiring higher systemic gas flows and greater use of phenylephrine to maintain desired hemodynamics. EDVH was associated with systemic absorption of CO(2). Greater absorption was more likely in difficult procedures and was associated with greater hemodynamic changes requiring medical therapy.

  17. Effect of flow rate and temperature on transmembrane blood pressure drop in an extracorporeal artificial lung.

    Science.gov (United States)

    Park, M; Costa, E L V; Maciel, A T; Barbosa, E V S; Hirota, A S; Schettino, G de P; Azevedo, L C P

    2014-11-01

    Transmembrane pressure drop reflects the resistance of an artificial lung system to blood transit. Decreased resistance (low transmembrane pressure drop) enhances blood flow through the oxygenator, thereby, enhancing gas exchange efficiency. This study is part of a previous one where we observed the behaviour and the modulation of blood pressure drop during the passage of blood through artificial lung membranes. Before and after the induction of multi-organ dysfunction, the animals were instrumented and analysed for venous-venous extracorporeal membrane oxygenation, using a pre-defined sequence of blood flows. Blood flow and revolutions per minute (RPM) of the centrifugal pump varied in a linear fashion. At a blood flow of 5.5 L/min, pre- and post-pump blood pressures reached -120 and 450 mmHg, respectively. Transmembrane pressures showed a significant spread, particularly at blood flows above 2 L/min; over the entire range of blood flow rates, there was a positive association of pressure drop with blood flow (0.005 mmHg/mL/minute of blood flow) and a negative association of pressure drop with temperature (-4.828 mmHg/(°Celsius). These associations were similar when blood flows of below and above 2000 mL/minute were examined. During its passage through the extracorporeal system, blood is exposed to pressure variations from -120 to 450 mmHg. At high blood flows (above 2 L/min), the drop in transmembrane pressure becomes unpredictable and highly variable. Over the entire range of blood flows investigated (0-5500 mL/min), the drop in transmembrane pressure was positively associated with blood flow and negatively associated with body temperature. © The Author(s) 2014.

  18. Inhibition of coronary blood flow by a vascular waterfall mechanism.

    Science.gov (United States)

    Downey, J M; Kirk, E S

    1975-06-01

    The mechanism whereby systole inhibits coronary blood flow was examined. A branch of the left coronary artery was maximally dilated with an adenosine infusion, and the pressure-flow relationship was obtained for beating and arrested states. The pressure-flow curve for the arrested state was shifted toward higher pressures and in the range of pressures above peak ventricular pressure was linear and parallel to that for the arrested state. Below this range the curve for the beating state converged toward that for the arrested state and was convex to the pressure axis. These results were compared with a model of the coronary vasculature that consisted of numerous parallel channels, each responding to local intramyocardial pressure by forming vascular waterfalls. When intramyocardial pressure in the model was assigned values from zero at the epicardium to peak ventricular pressure at the endocardium, pressure-flow curves similar to the experimental ones resulted. Thus, we conclude that systole inhibits coronary perfusion by the formation of vascular waterfalls and that the intramyocardial pressures responsible for this inhibition do not significantly exceed peak ventricular pressure.

  19. Xenon-133 determination of muscle blood flow: Use in evaluating cardioactive drugs

    International Nuclear Information System (INIS)

    Wexler, J.P.; Davis, L.; Mancini, D.; Chadwick, B.; Le Jemtel, T.

    1985-01-01

    Cardioactive drugs may effect both the central and peripheral circulatory systems. The effects on the central and peripheral circulatory systems of chronic Captorpril therapy in 7 pts with severe congestive heart failure (CHF) were evaluated simultaneously. Skeletal muscle blood flow (SMBF) determined using 133-Xe washout and a Cd/Te detector, oxygen consumption (VO/sub 2/), and radial artery and femoral vein O/sub 2/ concentration difference (A-V) were determined at rest and peak upright bicycle exercise before (BT) and after (AT) 6-12 weeks of Captopril therapy. In CI pts there was a significant increase in VO/sub 2/ and SMBF AT vs BT. In contrast, in CNC pts there was no change in VO/sub 2/ and a significant decrease in SMBF AT vs BT. In pts with severe CHF who are CI, there is an apparent fall in peripheral vascular resistance (PVR). In contrast, in CNC pts there is an increase in PVR. This study demonstrates that SMBF determines using 133-Xe is an important method for determining the effects of cardioactive drugs

  20. Stent revascularization restores cortical blood flow and reverses tissue hypoxia in atherosclerotic renal artery stenosis but fails to reverse inflammatory pathways or glomerular filtration rate.

    Science.gov (United States)

    Saad, Ahmed; Herrmann, Sandra M S; Crane, John; Glockner, James F; McKusick, Michael A; Misra, Sanjay; Eirin, Alfonso; Ebrahimi, Behzad; Lerman, Lilach O; Textor, Stephen C

    2013-08-01

    Atherosclerotic renal artery stenosis (ARAS) is known to reduce renal blood flow, glomerular filtration rate (GFR) and amplify kidney hypoxia, but the relationships between these factors and tubulointerstitial injury in the poststenotic kidney are poorly understood. The purpose of this study was to examine the effect of renal revascularization in ARAS on renal tissue hypoxia and renal injury. Inpatient studies were performed in patients with ARAS (n=17; >60% occlusion) before and 3 months after stent revascularization, or in patients with essential hypertension (n=32), during fixed Na(+) intake and angiotensin converting enzyme/angiotensin receptors blockers Rx. Single kidney cortical, medullary perfusion, and renal blood flow were measured using multidetector computed tomography, and GFR by iothalamate clearance. Tissue deoxyhemoglobin levels (R(2)*) were measured by blood oxygen level-dependent MRI at 3T, as was fractional kidney hypoxia (percentage of axial area with R(2)*>30/s). In addition, we measured renal vein levels of neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α. Pre-stent single kidney renal blood flow, perfusion, and GFR were reduced in the poststenotic kidney. Renal vein neutrophil gelatinase-associated lipocalin, tumor necrosis factor-α, monocyte chemoattractant protein-1, and fractional hypoxia were higher in untreated ARAS than in essential hypertension. After stent revascularization, fractional hypoxia fell (Pblood flow, whereas GFR and neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α remained unchanged. These data demonstrate that despite reversal of renal hypoxia and partial restoration of renal blood flow after revascularization, inflammatory cytokines and injury biomarkers remained elevated and GFR failed to recover in ARAS. Restoration of vessel patency alone failed to reverse tubulointerstitial damage and partly

  1. X-ray PIV measurements of blood flows without tracer particles

    International Nuclear Information System (INIS)

    Kim, Guk Bae; Lee, Sang Joon

    2006-01-01

    We analyzed the non-Newtonian flow characteristics of blood moving in a circular tube flow using an X-ray PIV method and compared the experimental results with hemodynamic models. The X-ray PIV method was improved for measuring quantitative velocity fields of blood flows using a coherent synchrotron X-ray. Without using any contrast media, this method can visualize flow pattern of blood by enhancing the phase-contrast and interference characteristics of blood cells. The enhanced X-ray images were achieved by optimizing the sample-to-scintillator distance, the sample thickness, and hematocrit in detail. The quantitative velocity fields of blood flows inside opaque conduits were obtained by applying a two-frame PIV algorithm to the X-ray images of the blood flows. The measured velocity data show typical features of blood flow such as the yield stress and shear-thinning effects. (orig.)

  2. Relationship between level of forage intake, blood flow and oxygen consumption by splanchnic tissues of sheep fed a tropical grass forage.

    Science.gov (United States)

    Hentz, F; Kozloski, G V; Zeni, D; Brun, M V; Stefanello, S

    2017-02-01

    Four Polwarth castrated male sheep (42 ± 4.4 kg live weight (LW) surgically implanted with chronic indwelling catheters into the mesenteric, portal and hepatic veins, housed in metabolism cages and offered Cynodon sp. hay at rates (g of dry matter (DM)/kg LW) of 7, 14, 21 or ad libitum, were used in a 4 × 4 Latin square experiment to evaluate the effect of the level of forage intake on blood flow and oxygen consumption by the portal-drained viscera (PDV), liver and total splanchnic tissues (ST). The portal blood flow and the oxygen consumption by PDV linearly increased at increased organic matter (OM) intake. No effect of level of OM intake was obtained for the hepatic artery blood flow and oxygen consumption by liver. As a consequence, the level of OM intake only tended to directly affect hepatic blood flow and oxygen consumption by total ST. Oxygen consumption was linearly and positively related to blood flow across PDV, liver and total ST. The heat production by PDV and total ST, as proportion of metabolizable energy (ME) intake, decreased curvilinearly at increased ME intake. In conclusion, the oxygen consumption by PDV, but not by liver, was directly related to the level of forage intake by sheep. Moreover, when ingested at levels below maintenance, most of ME was spent as heat produced by ST. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  3. Clinical quantitative study of therapeutic effect of partial splenic embolization (PSE) on portal vein hemodynamics

    International Nuclear Information System (INIS)

    Li Zhengran; Shan Hong; Zhu Kangshun; Jiang Zaibo; Guan Shouhai; Huang Mingsheng

    2002-01-01

    Objective: To research the changes of blood flow and pressure of the portal vein at both pre-and post-PSE. Methods: The blood flows of the portal vein (PV), splenic vein (SV), and superior mesentery vein (SMV) were measured by using color Doppler in 31 cases with clinically proved hepatic cirrhosis and hypersplenism at both pre- and post-PSE. The pressure of the portal vein and its branches was measured by percutaneous and trans-spleen portal venous catheterization, respectively both pre- and post-embolization in 11 cases of them. Results: The blood flow of PV, SV and SMV decreased significantly in all 31 cases after PSE (P < 0.05). The decreased degrees of blood flow of both PV and SV after PSE were positively related to the embolization degree (r = 0.589, P = 0.002 for PV; r= 0.862, P < 0.001 for SV). In 11 cases whose embolization degrees were more than 60%, the pressure of PV, SV and SMV decreased significantly after embolization (P<0.001). The decrease degree was (22.2 +- 5.8)%, (28.5 +- 1.7)% and (19.5 +- 8.1)%, respectively. The decreased degrees of pressure of both PV and SV after PSE were also positively related to the embolization degree (r = 0.645, P = 0.032 for PV; r = 0.687, P = 0.020 for SV). Conclusion: The embolization degree ranged from 60% to 80% may ameliorate peripheral blood WBC and PLT count, significantly decrease the blood flow and depress the pressure of portal vein, and relieve esophageal and gastric varices

  4. Effect of anti-vertigo granule on the opening number and blood flow of mouse ear capillary network

    Science.gov (United States)

    Li, Chongxian; Liu, Xiaobin; Li, Jun; Hao, Shaojun; Wang, Xidong; Li, Wenjun; Zhang, Zhengchen

    2018-04-01

    To observe the effects of anti-glare particles on the open number and blood flow in the auricle of mice with microcirculation disturbance model. Sixty mice, half male and half female, were randomly divided into 6 groups. The mice were given Kangxuan granule suspension, serum brain granule suspension and normal saline of the same volume, respectively, once a day. The mice were anesthetized by intraperitoneal injection of chloral hydrate at 1 hour after the last administration. The mouse was fixed on the observation platform and the auricle was placed on the transmission stage. BZ-2000 microcirculation microscope and microcirculation analysis system were used to observe the changes of blood velocity and capillary opening volume in auricle of mice before administration. The changes of blood velocity and capillaries opening volume of mouse auricle were observed 2 min after epinephrine injection into tail vein of mice. Bear fruit: Compared with those before epinephrine, the opening number of capillary reticulum of auricle in large dose Kangxuan granule group was significantly decreased (Pgroup and middle group. In the small dose Kangxuan granule group, the opening number of capillary network of auricle decreased significantly (Pgroup, the large dose Kangxuan granule group could significantly increase the opening number of the auricle capillary network in mice (Pgroup could significantly increase the opening number of auricle capillary reticulum in mice (Pgroup by Ridit test. Both Kangxuan granule group and Yangxuannao granule group could significantly improve the auricle hair of mice with microcirculation disorder. The blood flow in fine blood vessels (Pblood flow in mice with microcirculation disorder.

  5. Symptom correlates of cerebral blood flow following acute concussion

    Directory of Open Access Journals (Sweden)

    Nathan W. Churchill

    Full Text Available Concussion is associated with significant symptoms within hours to days post-injury, including disturbances in physical function, cognition, sleep and emotion. However, little is known about how subjective impairments correlate with objective measures of cerebrovascular function following brain injury. This study examined the relationship between symptoms and cerebral blood flow (CBF in individuals following sport-related concussion. Seventy university level athletes had CBF measured using Arterial Spin Labelling (ASL, including 35 with acute concussion and 35 matched controls and their symptoms were assessed using the Sport Concussion Assessment Tool 3 (SCAT3. For concussed athletes, greater total symptom severity was associated with elevated posterior cortical CBF, although mean CBF was not significantly different from matched controls (p=0.46. Examining symptom clusters, athletes reporting greater cognitive symptoms also had lower frontal and subcortical CBF, relative to athletes with greater somatic symptoms. The “cognitive” and “somatic” subgroups also exhibited significant differences in CBF relative to controls (p≤0.026. This study demonstrates objective CBF correlates of symptoms in recently concussed athletes and shows that specific symptom clusters may have distinct patterns of altered CBF, significantly extending our understanding of the neurobiology of concussion and traumatic brain injury. Keywords: Sport concussion, Cerebral blood flow, ASL, Symptoms

  6. Measurement of regional cerebral blood flow by positron emission tomography

    International Nuclear Information System (INIS)

    Herscovitch, P.; Powers, W.J.

    1987-01-01

    The principal advantage of positron emission tomography over other methods for measuring cerebral blood flow stems from the accurate, quantitative three-dimensional measurements of regional brain radioactivity that are possible with this technique. As a result, accurate quantitative measurements of regional cerebral blood flow can be obtained for both superficial and deep cerebral structures. The value of PET for investigating central nervous system physiology and pathology extends far beyond this, however. Through the use of different radiotracers and appropriate mathematical models, PET can be applied to the measurement of a wide variety of physiologic variables. Measurements of rCBF tell only part of the story. Experience with PET and with a variety of other techniques has taught us that rCBF is at times a poor indicator of the metabolic, functional, and biochemical status of cerebral tissue. It is only by understanding the interaction of all of these factors that our understanding of neurologic disease can advance. It is in the investigation of these complex relationships that the real value of PET resides

  7. Multiscale modeling and simulation of brain blood flow

    Energy Technology Data Exchange (ETDEWEB)

    Perdikaris, Paris, E-mail: parisp@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Grinberg, Leopold, E-mail: leopoldgrinberg@us.ibm.com [IBM T.J Watson Research Center, 1 Rogers St, Cambridge, Massachusetts 02142 (United States); Karniadakis, George Em, E-mail: george-karniadakis@brown.edu [Division of Applied Mathematics, Brown University, Providence, Rhode Island 02912 (United States)

    2016-02-15

    The aim of this work is to present an overview of recent advances in multi-scale modeling of brain blood flow. In particular, we present some approaches that enable the in silico study of multi-scale and multi-physics phenomena in the cerebral vasculature. We discuss the formulation of continuum and atomistic modeling approaches, present a consistent framework for their concurrent coupling, and list some of the challenges that one needs to overcome in achieving a seamless and scalable integration of heterogeneous numerical solvers. The effectiveness of the proposed framework is demonstrated in a realistic case involving modeling the thrombus formation process taking place on the wall of a patient-specific cerebral aneurysm. This highlights the ability of multi-scale algorithms to resolve important biophysical processes that span several spatial and temporal scales, potentially yielding new insight into the key aspects of brain blood flow in health and disease. Finally, we discuss open questions in multi-scale modeling and emerging topics of future research.

  8. Imaging of the bronchial blood flow using RI-angiography

    International Nuclear Information System (INIS)

    Fujii, Tadashige; Hirayama, Jiro; Kanai, Hisakata; Kobayashi, Toshio; Handa, Kenjiro

    1979-01-01

    RI-angiography with sup(99m)TcO 4 - was carried out using a scintillation camera with a digital minicomputer for the purpose of imaging of bronchial blood flow in various lung diseases, and as application of dual radioisotope techniques, other imagings such as tumor imaging with 197 HgCl 2 or 67 Ga-citrate and/or perfusion imaging with sup(99m)Tc-MAA, were performed simultaneously in patients remaining the same position, too. The image as a iso-count map extracted out of the image of 197 HgCl 2 , 67 Ga-citrate or sup(99m)Tc-MAA, was superimposed to the brightness image of RI-angiogram (aortic phase). By these procedures, the image of bronchial blood flow were obtained in some patients with lung cancer, pulmonary tuberculosis, lung abscess, and chronic bronchitis. The dual radioisotope techniques using RI-angiography and the other imaging were useful to make isotope diagnosis of lung diseases more reliable, and the image superimposition methods using RI-angiogram and the image of tumor of perfusion, were useful to improve anatomic orientation of the former. (author)

  9. Adipose tissue and skeletal muscle blood flow during mental stress

    Energy Technology Data Exchange (ETDEWEB)

    Linde, B.; Hjemdahl, P.; Freyschuss, U.; Juhlin-Dannfelt, A.

    1989-01-01

    Mental stress (a modified Stroop color word conflict test (CWT)) increased adipose tissue blood flow (ATBF; 133Xe clearance) by 70% and reduced adipose tissue vascular resistance (ATR) by 25% in healthy male volunteers. The vasculatures of adipose tissue (abdomen as well as thigh), skeletal muscle of the calf (133Xe clearance), and the entire calf (venous occlusion plethysmography) responded similarly. Arterial epinephrine (Epi) and glycerol levels were approximately doubled by stress. Beta-Blockade by metoprolol (beta 1-selective) or propranolol (nonselective) attenuated CWT-induced tachycardia similarly. Metoprolol attenuated stress-induced vasodilation in the calf and tended to do so in adipose tissue. Propranolol abolished vasodilation in the calf and resulted in vasoconstriction during CWT in adipose tissue. Decreases in ATR, but not in skeletal muscle or calf vascular resistances, were correlated to increases in arterial plasma glycerol (r = -0.42, P less than 0.05), whereas decreases in skeletal muscle and calf vascular resistances, but not in ATR, were correlated to increases in arterial Epi levels (r = -0.69, P less than 0.01; and r = -0.43, P less than 0.05, respectively). The results suggest that mental stress increases nutritive blood flow in adipose tissue and skeletal muscle considerably, both through the elevation of perfusion pressure and via vasodilatation. Withdrawal of vasoconstrictor nerve activity, vascular beta 2-adrenoceptor stimulation by circulating Epi, and metabolic mechanisms (in adipose tissue) may contribute to the vasodilatation.

  10. Adipose tissue and skeletal muscle blood flow during mental stress

    International Nuclear Information System (INIS)

    Linde, B.; Hjemdahl, P.; Freyschuss, U.; Juhlin-Dannfelt, A.

    1989-01-01

    Mental stress [a modified Stroop color word conflict test (CWT)] increased adipose tissue blood flow (ATBF; 133Xe clearance) by 70% and reduced adipose tissue vascular resistance (ATR) by 25% in healthy male volunteers. The vasculatures of adipose tissue (abdomen as well as thigh), skeletal muscle of the calf (133Xe clearance), and the entire calf (venous occlusion plethysmography) responded similarly. Arterial epinephrine (Epi) and glycerol levels were approximately doubled by stress. Beta-Blockade by metoprolol (beta 1-selective) or propranolol (nonselective) attenuated CWT-induced tachycardia similarly. Metoprolol attenuated stress-induced vasodilation in the calf and tended to do so in adipose tissue. Propranolol abolished vasodilation in the calf and resulted in vasoconstriction during CWT in adipose tissue. Decreases in ATR, but not in skeletal muscle or calf vascular resistances, were correlated to increases in arterial plasma glycerol (r = -0.42, P less than 0.05), whereas decreases in skeletal muscle and calf vascular resistances, but not in ATR, were correlated to increases in arterial Epi levels (r = -0.69, P less than 0.01; and r = -0.43, P less than 0.05, respectively). The results suggest that mental stress increases nutritive blood flow in adipose tissue and skeletal muscle considerably, both through the elevation of perfusion pressure and via vasodilatation. Withdrawal of vasoconstrictor nerve activity, vascular beta 2-adrenoceptor stimulation by circulating Epi, and metabolic mechanisms (in adipose tissue) may contribute to the vasodilatation

  11. Effect of aerosolized acetylcholine on bronchial blood flow.

    Science.gov (United States)

    Charan, N B; Carvalho, P; Johnson, S R; Thompson, W H; Lakshminarayan, S

    1998-08-01

    We studied the effects of aerosolized as well as intravenous infusion of acetylcholine on bronchial blood flow in six anesthetized sheep. Intravenous infusion of acetylcholine, at a dose of 2 microg/kg, increased bronchial blood flow from 45 +/- 15 (SE) to 74 +/- 30 ml/min, and vascular conductance increased by 76 +/- 22%. In contrast, aerosolized acetylcholine at doses of 2 and 20 microg/kg decreased bronchial vascular conductance by approximately 10%. At an aerosolized dose of 200 microg/kg, the bronchial vascular conductance increased by approximately 15%, and there was no further increase in conductance when the aerosolized dose was increased to 2,000 microg/kg. Pretreatment of animals with a nitric oxide synthase inhibitor, Nomega-nitro-L-arginine methyl ester hydrochloride, partially blocked the vasodilatory effects of intravenous acetylcholine and completely blocked the vasodilatory effects of high-dose aerosolized acetylcholine. These data suggest that aerosolized acetylcholine does not readily penetrate the vascular wall of bronchial circulatory system and, therefore, has minimal vasodilatory effects on the bronchial vasculature.

  12. Cerebral blood flow (CBF) with 133Xe inhalation method

    International Nuclear Information System (INIS)

    Kusunoki, Tadaki; Masumura, Michio; Tamaki, Norihiko; Matsumoto, Satoshi; Yamashita, Hideyuki.

    1982-01-01

    The effects of CO 2 inhalation on the cerebral blood flow (CBF) were examined with 133 Xe inhalation method (Novo Inhalation Cerebrograph) on 9 normal peoples and 20 patients. Nine normal peoples were divided into 3 groups consisting of each 3 peoples, namely young age group, middle age group, and old age group. Each increased CBF (%) by CO 2 inhalation was 40 -- 44 in young age group, 36 -- 37 in middle age group, and 35 -- 36 in old age group in the blood flow of the first compartment (F 1 ), and 27 -- 28 in young age group, 30 -- 31 in middle age group and 23 -- 24 in old age group in the initial slope index (ISI). Each CO 2 reactivity factor (RF) was 5.5 -- 5.8 in young age group, 3.8 -- 4.0 in middle age group and 3.3 in old age group in F 1 , and 3.1 -- 3.2 in young age group, 2.0 -- 3.3 in middle age group, and 1.2 -- 1.3 in old age group in ISI. Twenty patients consisted of 15 patients of occlusive cerebrovascular disease, 2 patients of head injury, 2 patients of normal pressure hydrocephalus and one patient of subarachnoid hemorrhage. RF was abnormally lower than normal value in 5 patients in F 1 , but in 7 in ISI. Clinical benefits of CBF study during CO 2 inhalation with 133 Xe inhalation method were discussed. (author)

  13. Regional cerebral blood flow in SPECT pattern in Parkinson's disease

    International Nuclear Information System (INIS)

    Lenart-Jankowska, D.; Junik, R.; Sowinski, J.; Gembicki, M.; Wender, M.

    1997-01-01

    The purpose of our work was to compare the regional cerebral blood flow (rCBF) in SPECT examination in Parkinson's disease with (17 cases) and without (7 cases) dementia and in various clinical stages of the disease. The patients underwent SPECT examination 5-40 min after intravenous application of HMPAO (Ceretec, Amersham) with 740 Mbq (20 mCi) pertechnate 99m Tc. SPECT was performed with a Siemens Diacam single-head rotating gamma camera coupled to a high resolution collimator and Icon computer system provided by the manufacturer. The results were defined in relative values of ROI in relation to cerebellum. Patients with Parkinson's disease showed hypoperfusion in cerebral lobes and in deep cerebral structures including the basal ganglia. Regional perfusion deficit in SPECT was seen with and without associated dementia and already in early stage of the disease. Parkinson's disease is provoked by the lesions of dopaminergic neurons of the central nervous system leading to domination of extrapyramidal symptoms. There are many indications that also the neurotransmitters associated with cognitive functions as acetylcholine demonstrate some abnormalities. However, only in some cases of Parkinson's disease dementia is the dominating symptom. Our results of regional cerebral blood flow testify that in Parkinson's disease the dysfunction of the central nervous system is more diffuse than has previously been suggested. (author)

  14. Cerebral blood flow autoregulation during intracranial hypertension in hypoxic lambs

    International Nuclear Information System (INIS)

    Borel, C.O.; Backofen, J.E.; Koehler, R.C.; Jones, M.D. Jr.; Traystman, R.J.

    1987-01-01

    The authors tested the hypothesis that hypoxic hypoxia interferes with cerebral blood flow (CBF) autoregulation when intracranial pressure (ICP) is elevated in pentobarbital-anesthetized lambs (3 to 9 days old). Cerebral perfusion pressure (CPP) was lowered stepwise from 73 to 23 mmHg in eight normoxic lambs and from 65 to 31 mmHg in eight other hypoxic lambs by ventricular infusion of artificial cerebrospinal fluid. In normoxic lambs, CBF measured by microspheres labeled with six different radioisotopes was not significantly changed over this range of CPP. In animals made hypoxic, base-line CBF was twice that of normoxic lambs. CBF was unchanged as CPP was reduced to 31 mmHg. Lower levels of CPP were not attained because a pressor response occurred with further elevations of ICP. No regional decrements in blood flow to cortical arterial watershed areas or to more caudal regions, such as cerebellum, brain stem, or thalamus, were detected with elevated ICP. Cerebral O 2 uptake was similar in both groups and did not decrease when CPP was reduced. These results demonstrate that normoxic lambs have a considerable capacity for effective autoregulation of CBF when ICP is elevated. Moreover, cerebral vasodilation in response to a level of hypoxia approximating that normally seen prenatally does not abolish CBF autoregulation when ICP is elevated during the first postnatal week

  15. Alterations of Regional Cerebral Blood Flow in Major Depressive Disorder

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Hyoung; Chung, Yong An; Seo, Ye Young; Yoo, Ik Dong; Na, Sae Jung; Jung, Hyun Suk; Kim, Ki Jun [College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)

    2009-04-15

    The authors analyzed how the regional cerebral blood flow (rCBF) findings of patients with major depression differ from the normal control, and our results were compared to previous reports. Twelve patients fulfilling DSM-IV criteria for major depression who were off all psychotropic medications for > 4 weeks (male: 7, female: 5, age range: 19approx52 years, average age: 29.3+-9.9 years) and 14 normal volunteers (male: 8, female: 6, age range: 19approx53 years, average age: 31.4+-9.2 years) were recruited. Images of brain perfusion SPECT were obtained using Tc-99m ECD and patterns of the rCBF were compared between patients with major depression and the healthy control subjects. The patients with major depression showed increase of the r-CBF in right lingual gyrus, right fusiform gyrus, left lingual gyrus, left precuneus, and left superior temporal gyrus, and showed decrease of r-CBF in right pons, left medial frontal gyrus, cingulate gyrus of left limbic lobe, cingulate gyrus of right frontal lobe, and cingulate gyrus of right limbic lobe compared to the normal control. The Tc-99m ECD brain perfusion SPECT findings in our study did not differ from the previously reported regional cerebral blood flow pattern of patients with major depression. Especially, decreased rCBF pattern typical to major depression patients in the right pons, left medial frontal gyrus, and cingulate regions was clearly demonstrated

  16. Alterations of Regional Cerebral Blood Flow in Major Depressive Disorder

    International Nuclear Information System (INIS)

    Lee, Won Hyoung; Chung, Yong An; Seo, Ye Young; Yoo, Ik Dong; Na, Sae Jung; Jung, Hyun Suk; Kim, Ki Jun

    2009-01-01

    The authors analyzed how the regional cerebral blood flow (rCBF) findings of patients with major depression differ from the normal control, and our results were compared to previous reports. Twelve patients fulfilling DSM-IV criteria for major depression who were off all psychotropic medications for > 4 weeks (male: 7, female: 5, age range: 19∼52 years, average age: 29.3±9.9 years) and 14 normal volunteers (male: 8, female: 6, age range: 19∼53 years, average age: 31.4±9.2 years) were recruited. Images of brain perfusion SPECT were obtained using Tc-99m ECD and patterns of the rCBF were compared between patients with major depression and the healthy control subjects. The patients with major depression showed increase of the r-CBF in right lingual gyrus, right fusiform gyrus, left lingual gyrus, left precuneus, and left superior temporal gyrus, and showed decrease of r-CBF in right pons, left medial frontal gyrus, cingulate gyrus of left limbic lobe, cingulate gyrus of right frontal lobe, and cingulate gyrus of right limbic lobe compared to the normal control. The Tc-99m ECD brain perfusion SPECT findings in our study did not differ from the previously reported regional cerebral blood flow pattern of patients with major depression. Especially, decreased rCBF pattern typical to major depression patients in the right pons, left medial frontal gyrus, and cingulate regions was clearly demonstrated

  17. Altered Cerebral Blood Flow Covariance Network in Schizophrenia.

    Science.gov (United States)

    Liu, Feng; Zhuo, Chuanjun; Yu, Chunshui

    2016-01-01

    Many studies have shown abnormal cerebral blood flow (CBF) in schizophrenia; however, it remains unclear how topological properties of CBF network are altered in this disorder. Here, arterial spin labeling (ASL) MRI was employed to measure resting-state CBF in 96 schizophrenia patients and 91 healthy controls. CBF covariance network of each group was constructed by calculating across-subject CBF covariance between 90 brain regions. Graph theory was used to compare intergroup differences in global and nodal topological measures of the network. Both schizophrenia patients and healthy controls had small-world topology in CBF covariance networks, implying an optimal balance between functional segregation and integration. Compared with healthy controls, schizophrenia patients showed reduced small-worldness, normalized clustering coefficient and local efficiency of the network, suggesting a shift toward randomized network topology in schizophrenia. Furthermore, schizophrenia patients exhibited altered nodal centrality in the perceptual-, affective-, language-, and spatial-related regions, indicating functional disturbance of these systems in schizophrenia. This study demonstrated for the first time that schizophrenia patients have disrupted topological properties in CBF covariance network, which provides a new perspective (efficiency of blood flow distribution between brain regions) for understanding neural mechanisms of schizophrenia.

  18. [Cockett's syndrome, May-Thurner syndrome, or iliac vein compression syndrome].

    Science.gov (United States)

    Gil Martín, A R; Carreras Aja, M; Arrieta Ardieta, I; Labayen Azparren, I

    2014-01-01

    Iliac vein compression syndrome (also known as May-Thurner syndrome or Cockett's syndrome) is a rare clinical entity in which the left common iliac vein is compressed when it passes between the right common iliac artery and the spine. The sustained compression and trauma caused by the pulsatile force of the artery on the vein damage the intima and lead to the formation of membranes or bands in the vascular lumen that hinder or obstruct the flow of blood in the vein, favoring thrombus formation. The current treatment strategy of choice is endovascular vein patch angioplasty and stenting with the aim of improving the caliber of the lumen and enabling normal venous drainage. We present two cases of May-Thurner syndrome and review the clinical and CT findings. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  19. Portal venous stent placement for treatment of portal hypertension caused by benign main portal vein stenosis.

    Science.gov (United States)

    Shan, Hong; Xiao, Xiang-Sheng; Huang, Ming-Sheng; Ouyang, Qiang; Jiang, Zai-Bo

    2005-06-07

    To evaluate the value of endovascular stent in the treatment of portal hypertension caused by benign main portal vein stenosis. Portal vein stents were implanted in six patients with benign main portal vein stenosis (inflammatory stenosis in three cases, postprocedure of liver transplantation in another three cases). Changes in portal vein pressure, portal vein patency, relative clinical symptoms, complications, and survival were evaluated. Six metallic stents were successfully placed across the portal vein stenotic or obstructive lesions in six patients. Mean portal venous pressure decreased significantly after stent implantation from (37.3+/-4.7) cm H(2)O to (18.0+/-1.9) cm H(2)O. The portal blood flow restored and the symptoms caused by portal hypertension were eliminated. There were no severe procedure-related complications. The patients were followed up for 1-48 mo. The portal vein remained patent during follow-up. All patients survived except for one patient who died of other complications of liver transplantation. Percutaneous portal vein stent placement for the treatment of portal hypertension caused by benign main portal vein stenosis is safe and effective.

  20. Regional heterogeneity of endothelial cells in the porcine vortex vein system.

    Science.gov (United States)

    Tan, Priscilla Ern Zhi; Yu, Paula K; Cringle, Stephen J; Morgan, William H; Yu, Dao-Yi

    2013-09-01

    The aim of this study was to investigate whether region-dependent endothelial heterogeneity is present within the porcine vortex vein system. The superior temporal vortex vein in young adult pig eyes were dissected out and cannulated. The intact vortex vein system down to the choroidal veins was then perfused with labels for f-actin and nucleic acid. The endothelial cells within the choroidal veins, pre-ampulla, anterior portion of the ampulla, mid-ampulla, posterior portion of the ampulla, post-ampulla, intra-scleral canal and the extra-ocular vortex vein regions were studied in detail using a confocal microscopy technique. The endothelial cell and nuclei length, width, area and perimeter were measured and compared between the different regions. Significant regional differences in the endothelial cell and nuclei length, width, area and perimeter were observed throughout the porcine vortex vein system. Most notably, very narrow and elongated endothelia were found in the post-ampulla region. A lack of smooth muscle cells was noted in the ampulla region compared to other regions. Heterogeneity in endothelial cell morphology is present throughout the porcine vortex vein system and there is a lack of smooth muscle cells in the ampulla region. This likely reflects the highly varied haemodynamic conditions and potential blood flow control mechanisms in different regions of the vortex vein system. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Treatment of portal hypertension caused by benign main portal vein stenosis with endovascular stent

    International Nuclear Information System (INIS)

    Huang Mingsheng; Shan Hong; Jiang Zaibo; Guan Shouhai; Zhu Kangshun; Li Zhengran; Zhou Yubin; He Bingjun

    2004-01-01

    Objective: To evaluate the value of endovascular stent in the treatment of portal hypertension caused by benign main portal vein stenosis. Methods: Portal vein stents were implanted in 6 patients with benign main portal vein stenosis (inflammatory stenosis in 3 cases, postprocedure of liver transplantation in another 3 cases). The change of portal vein pressure, the patency of portal vein, relative clinical symptoms, complications, and survival were evaluated. Results: Six metallic stents were successfully placed across the portal vein stenotic or obstructive lesions in all 6 patients. Mean portal venous pressure decreased significantly after stent implantation from (37.3 ± 4.7) cm H 2 O (1 cm H 2 O=0.098 kPa) to (18.0 ± 1.9) cm H 2 O (P<0.001). The portal blood flow was restored, and the symptoms caused by portal hypertension were eliminated. There was no severe procedure-related complication. Follow-up time was from 5 to 36 months. The portal vein remained patent during the follow-up. All patients survived except one patient who died of other complications of liver transplantation. Conclusion: Percutaneous portal vein stent placement for the treatment of the benign main portal vein stenosis is safe and effective. (authors)

  2. Relationship between retinal blood flow and arterial oxygen.

    Science.gov (United States)

    Cheng, Richard W; Yusof, Firdaus; Tsui, Edmund; Jong, Monica; Duffin, James; Flanagan, John G; Fisher, Joseph A; Hudson, Chris

    2016-02-01

    Vascular reactivity, the response of the vessels to a vasoactive stimulus such as hypoxia and hyperoxia, can be used to assess the vascular range of adjustment in which the vessels are able to compensate for changes in PO2. Previous studies in the retina have not accurately quantified retinal vascular responses and precisely targeted multiple PaO2 stimuli at the same time as controlling the level of carbon dioxide, thus precluding them from modelling the relationship between retinal blood flow and oxygen. The present study modelled the relationship between retinal blood flow and PaO2, showing them to be a combined linear and hyperbolic function. This model demonstrates that the resting tonus of the vessels is at the mid-point and that they have great vascular range of adjustment, compensating for decreases in oxygen above a PETCO2 of 32-37 mmHg but being limited below this threshold. Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia) but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modelled in the retina, particularly in the vascular reserve and resting tonus of the vessels. The present study aimed to determine the limitations of the retinal vasculature by modelling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for eight different blood gas conditions, with the end-tidal partial pressure of oxygen (PETCO2) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon laser blood flowmeter (Canon Inc., Tokyo, Japan) during the first visit and using Doppler spectral domain optical coherence tomography during the second visit. We determined that the relationship between RBF and PaO2 can be modelled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content

  3. Intraportal nicotine infusion in rats decreases hepatic blood flow through endothelin-1 and both endothelin A and endothelin B receptors

    International Nuclear Information System (INIS)

    Hashimoto, Takashi; Yoneda, Masashi; Shimada, Tadahito; Kurosawa, Mieko; Terano, Akira

    2004-01-01

    Smoking has been demonstrated to aggravate liver injury. Nicotine, a major pharmacological component of tobacco smoke, affects a multitude of functions. Smoking and nicotine induce synthesis of endothelin (ET)-1. The effect of intraportal infusion of nicotine on hepatic circulation and an involvement of ET-1 and ET receptor in the action of nicotine were investigated in rats. Nicotine (0-100 μg/kg/h) was infused into the portal vein of urethane-anesthetized rats, and changes of hepatic blood flow were evaluated. Intraportal infusion of nicotine dose-dependently decreased hepatic blood flow and increased portal pressure without any alteration of heart rate or arterial blood pressure. This action of intraportal nicotine was completely abolished by pretreatment of ET-1 antibody. Either BQ485 (ET A receptor antagonist) or BQ788 (ET B receptor antagonist) partially reversed the effect of nicotine, and combination of BQ788 and BQ485 completely abolished it. These findings suggest that nicotine inhibits hepatic circulation through ET-1, and ET A and ET B receptor

  4. Dynamic modeling of uteroplacental blood flow in IUGR indicates vortices and elevated pressure in the intervillous space - a pilot study

    Science.gov (United States)

    Roth, Christian J.; Haeussner, Eva; Ruebelmann, Tanja; Koch, Franz V.; Schmitz, Christoph; Frank, Hans-Georg; Wall, Wolfgang A.

    2017-01-01

    Ischemic placental disease is a concept that links intrauterine growth retardation (IUGR) and preeclampsia (PE) back to insufficient remodeling of uterine spiral arteries. The rheological consequences of insufficient remodeling of uterine spiral arteries were hypothesized to mediate the considerably later manifestation of obstetric disease. However, the micro-rheology in the intervillous space (IVS) cannot be examined clinically and rheological animal models of the human IVS do not exist. Thus, an in silico approach was implemented to provide in vivo inaccessible data. The morphology of a spiral artery and the inflow region of the IVS were three-dimensionally reconstructed to provide a morphological stage for the simulations. Advanced high-end supercomputing resources were used to provide blood flow simulations at high spatial resolution. Our simulations revealed turbulent blood flow (high-velocity jets and vortices) combined with elevated blood pressure in the IVS and increased wall shear stress at the villous surface in conjunction with insufficient spiral artery remodeling only. Post-hoc histological analysis of uterine veins showed evidence of increased trophoblast shedding in an IUGR placenta. Our data support that rheological alteration in the IVS is a relevant mechanism linking ischemic placental disease to altered structural integrity and function of the placenta.

  5. Cutaneous and subcutaneous blood flow measurements in psoriasis

    International Nuclear Information System (INIS)

    Klemp, P.

    1987-01-01

    The experiments - published in 7 papers in The Journal of Investigative Dermatology 1983-86 - have demonstrated: 1. The accuracy of the local 133 Xe washout method is about 15% for estimation of the cutaneous blood flow (CBF), and about 10% for subcutaneous blood flow measurements (SBF). In measurements of absolute CBF values a graphic curve resolution of the washout curve should alwaus be performed. Otherwise the CBF might be considerably underestimated. 2. CdTe(Cl) mini-detectors can be attached directly to the skin, and might yield measurements of both CBF and SBF that can substitute for those made with conventional detectors. 3. The laser Doppler measurements could not be correlated to quantitative measurements of the CBF. 4. The tissue-to-blood partition coefficient for 133 Xe of lesional psoriatic skin (LS) is increased. 5. In untreated, LS of patients with active psoriasis the CBF is about a factor of 10 times higher than the CBF of normal individuals. In non-lesional skin (NLS) of patients with active psoriasis the CBF is about a factor of 2 higher than the CBF of normal individuals. However, the CBF did not differ in NLS of patients with minimal skin manifestations. The high CBF decreases gradualy during antipsoriatic treatment. 6. A paradoxical autoregulation of the CBF was observed in LS. 7. The high CBF is not due to a maximally dilated vascular bed. 8. The SBF in LS areas was a factor of higher than the SBF in normal individuals. 9. A normal, local regulation of the SBF was found. (author)

  6. Total hepatofugal portal blood flow in cirrhosis demonstrated by transhepatic portography

    International Nuclear Information System (INIS)

    Burcharth, F.; Aagaard, J.; Herlev Hospital

    1988-01-01

    We investigated 108 patients with cirrhosis of the liver and portal hypertension by percutaneous transhepatic portography to demonstrate the occurrence and frequency of total hepatofugal portal blood flow. Sixteen patients (14.8%) had a total hepatofugal portal blood flow. The aetiology of portal hypertension and the portal pressure did not differ from that in the group of patients with hepatopetal portal blood flow. A significantly higher percentage of patients in the group with hepatofugal flow had gastro-oesophageal varices (P [de

  7. Type of aphasia and regional cerebral blood flow

    International Nuclear Information System (INIS)

    Tagawa, Koichi; Sugimoto, Keiko; Minematsu, Kazuo; Yamaguchi, Takenori; Naritomi, Hiroaki; Sawada, Tohru

    1982-01-01

    In 40 patients with aphasia due to cerebral infarction, regional cerebral blood flow (rCBF) was measured after 2 months of ictus with 133 Xe inhalation method. There were 18 cases with motor aphasia and 22 with sensory aphasia. On the measurements of rCBF, 3 detectors were placed over frontal region (group F), 3 over temporal region (group T), and remaining 3 over parietal region (group P), of the dominant hemisphere. The flow values were compared with the rCBF values obtained from 21 control subjects who had no abnormality in CT scan and on neurological examinations. The control subjects revealed the hyperfrontal pattern of flow distribution; rCBF values in groups F, T and P, which were expressed as an initial slope index, were 50.0 +- 4.8, 48.0 +- 5.1 and 47.4 +- 4.5, respectively. The hyperfrontal pattern was absent in cases with motor aphasia. In this group, rCBF in groups F, T and P were 42.0 +- 8.3, 44.7 +- 8.4 and 41.0 +- 8.5, respectively, and rCBF in frontal region was significantly reduced compared with that in the control group. In sensory aphasia, rCBF values in groups F, T and P were all significantly reduced compared to the controls showing 44.0 +- 5.7, 42.8 +- 5.1 and 40.6 +- 5.4, respectively. In this group, the hyperfrontal pattern was maintained at a low flow level. When absolute rCBF values were compared between motor and sensory aphasia, there was no significant difference between these 2 groups. However, regional flow distribution in motor aphasia was significantly different from that of sensory aphasia, and the cases having the lowest value in group F were more frequently found in the former than in the latter. (J.P.N.)

  8. Integrated Lateral Flow Device for Flow Control with Blood Separation and Biosensing

    Directory of Open Access Journals (Sweden)

    Veronica Betancur

    2017-12-01

    Full Text Available Lateral flow devices are versatile and serve a wide variety of purposes, including medical, agricultural, environmental, and military applications. Yet, the most promising opportunities of these devices for diagnosis might reside in point-of-care (POC applications. Disposable paper-based lateral flow strips have been of particular interest, because they utilize low-cost materials and do not require expensive fabrication instruments. However, there are constraints on tuning flow rates and immunoassays functionalization in papers, as well as technical challenges in sensors’ integration and concentration units for low-abundant molecular detection. In the present work, we demonstrated an integrated lateral flow device that applied the capillary forces with functionalized polymer-based microfluidics as a strategy to realize a portable, simplified, and self-powered lateral flow device (LFD. The polydimethylsiloxane (PDMS surface was rendered hydrophilic via functionalization with different concentrations of Pluronic F127. Controlled flow is a key variable for immunoassay-based applications for providing enough time for protein binding to antibodies. The flow rate of the integrated LFD was regulated by the combination of multiple factors, including Pluronic F127 functionalized surface properties and surface treatments of microchannels, resistance of the integrated flow resistor, the dimensions of the microstructures and the spacing between them in the capillary pump, the contact angles, and viscosity of the fluids. Various plasma flow rates were regulated and achieved in the whole device. The LFD combined the ability to separate high quality plasma from human whole blood by using a highly asymmetric plasma separation membrane, and created controlled and steady fluid flow using capillary forces produced by the interfacial tensions. Biomarker immunoglobulin G (IgG detection from plasma was demonstrated with a graphene nanoelectronic sensor integrated

  9. A comparison of dobutamine and levosimendan on hepatic blood flow in patients with a low cardiac output state after cardiac surgery: a randomised controlled study.

    Science.gov (United States)

    Alvarez, J; Baluja, A; Selas, S; Otero, P; Rial, M; Veiras, S; Caruezo, V; Taboada, M; Rodriguez, I; Castroagudin, J; Tome, S; Rodriguez, A; Rodriguez, J

    2013-11-01

    Liver dysfunction due to a low cardiac output state after cardiac surgery is associated with a poor prognosis, but whether one inotrope is superior to another in improving hepatic perfusion remains uncertain. This study compared the systemic and hepatic haemodynamic effects of levosimendan to dobutamine in patients with a low cardiac output state (cardiac index flow (ml/min): 614.0±124.7, 585.9±144.8; pulsatility index: 2.02±0,28, 2.98±0.27 versus the levosimendan group: cardiac index: 3.02± 0.27, 2.98± 0.30; portal vein flow: 723.0± 143.5, 702.9±117.8; pulsatility index: 1.71±0.26, 1.73±0.27). The improvement in portal vein blood flow at 48 hours was significantly better after levosimendan than dobutamine (41% vs. 11% increment from baseline, Pflow through both the hepatic artery and portal venous system, whereas dobutamine can only improve the portal venous blood flow without vasodilating the hepatic artery.

  10. Regional cerebral blood flow in patients with hypertensive intracerebral hemorrhage

    International Nuclear Information System (INIS)

    Kuroda, Kiyoshi

    1982-01-01

    Regional cerebral blood flow (rCBF) was measured in 36 patients with hypertensive intracerebral hemorrhage (putaminal hemorrhage) treated surgically, using the Xenon-133 intracarotid injection method. The correlations between CBF in four regions, (the hemisphere, the frontal region, the sensori-motor area and the focal area) and the duration from the operation, the conscious level, the hematoma volume and motor function were investigated. Mean cerebral blood flow (MCBF), rCBF in sensori-motor area and in the focal area showed a value below 30 ml/100g/min. for any duration after the operation within one year. However, in the frontal region rCBF tends to increase from 4 months after the operation. There was a close correlation between the conscious level and CBF, especially in the frontal region. The higher CBF was noted in the better consciousness group. In hematoma cases the larger the hematoma volume (especially those over 31 ml)the lower the CBF in all three regions. In the focal area rCBF showed the lowest value among these three regions and was dependent on the hematoma volume, while frontal region revealed the highest flow value of them all, even in cases with a hematoma volume over 81 ml. There was a significant difference in rCBF between cases with severe motor disturbance and cases with moderate motor disturbance, except in the focal area. In the frontal region rCBF coincides rather well to the degree of motor disturbance. While, rCBF in the focal area was less than 30 ml/100g/min., and showed no correlation to motor function. (J.P.N.)

  11. Analysis of blood flow patterns in aortic aneurysm by cine magnetic resonance imaging

    International Nuclear Information System (INIS)

    Matsuoka, Hiroshi

    1993-01-01

    Cine MRI (0.5 T) using rephased gradient echo technique was performed to study the patterns of blood flow in the aortic aneurysm of 16 patients with aortic aneurysm, and the data were compared with those of 5 healthy volunteers. In the transaxial section, the blood flow in normal aorta appeared as homogeneous high intensity during systole. On the other hand, the blood flow in the aneurysm appeared as inhomogeneous flow enhancement with flow void. In the sagittal scan, the homogeneous flow enhancement in a normal aorta was also observed during systole and its apex of flow enhancement was 'taper'. The blood flow patterns in the aneurysm were classified as 'irregular', 'zonal', 'eddy', and 'obscure' depending on the contrast of flow enhancement and flow void. Their apexes were 'taper' or 'round'. The blood flow patterns in the aneurysm were related to the size of aneurysm. In patients with a large size 'aneurysm, their flow patterns were 'eddy' or 'obscure' and the flow enhancement was 'round'. On the other hand, in patients with a small size aneurysm, their flow patterns were 'irregular' or 'zonal', and their flow enhancement was 'taper'. Though the exact mechanism of abnormal flow patterns in an aortic aneurysm remains to be determined, cine MRI gives helpful informations in assessing blood flow dynamics in the aneurysm. (author)

  12. Acute Liver Failure Due to Regorafenib May Be Caused by Impaired Liver Blood Flow: A Case Report.

    Science.gov (United States)

    Akamine, Takaki; Ando, Koji; Oki, Eiji; Saeki, Hiroshi; Nakashima, Yuichiro; Imamura, Y U; Ohgaki, Kippei; Maehara, Yoshihiko

    2015-07-01

    Regorafenib has been approved for treatment of patients with unresectable or recurrent gastrointestinal stromal tumors resistant to imatinib or sunitinib. However, regorafenib has severe side-effects, including acute liver failure. We describe the case of a patient with multiple liver metastases of a small intestinal stromal tumor who experienced acute liver failure while being treated with regorafenib. A 50-year-old patient with an unresectable small intestinal stromal tumor resistant to prior treatment with imatinib and sunitinib was started on regorafenib, but experienced acute liver failure 10 days later. Plasma exchange and steroid pulse treatment improved her liver function. During liver failure, abdominal ultrasonography showed to-and-fro flow in the portal vein. Lactate dehydrogenase concentration was markedly elevated to 1633 U/l. These findings indicate that liver failure in this patient was due to impaired liver blood flow. Regorafenib may impair liver blood flow, inducing acute liver failure. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  13. Automated measurement and classification of pulmonary blood-flow velocity patterns using phase-contrast MRI and correlation analysis.

    Science.gov (United States)

    van Amerom, Joshua F P; Kellenberger, Christian J; Yoo, Shi-Joon; Macgowan, Christopher K

    2009-01-01

    An automated method was evaluated to detect blood flow in small pulmonary arteries and classify each as artery or vein, based on a temporal correlation analysis of their blood-flow velocity patterns. The method was evaluated using velocity-sensitive phase-contrast magnetic resonance data collected in vitro with a pulsatile flow phantom and in vivo in 11 human volunteers. The accuracy of the method was validated in vitro, which showed relative velocity errors of 12% at low spatial resolution (four voxels per diameter), but was reduced to 5% at increased spatial resolution (16 voxels per diameter). The performance of the method was evaluated in vivo according to its reproducibility and agreement with manual velocity measurements by an experienced radiologist. In all volunteers, the correlation analysis was able to detect and segment peripheral pulmonary vessels and distinguish arterial from venous velocity patterns. The intrasubject variability of repeated measurements was approximately 10% of peak velocity, or 2.8 cm/s root-mean-variance, demonstrating the high reproducibility of the method. Excellent agreement was obtained between the correlation analysis and radiologist measurements of pulmonary velocities, with a correlation of R2=0.98 (P<.001) and a slope of 0.99+/-0.01.

  14. En bloc resection of skull base tumor including internal carotid artery. Preoperative evaluation of cerebral blood flow

    International Nuclear Information System (INIS)

    Okamoto, Yoshitaka; Matsuzaki, Zensei; Kamijo, Atsushi; Ogino, Jun; Nagaseki, Yoshishige; Nukui, Hideaki; Yokomizo, Michinori; Togawa, Kiyoshi

    1998-01-01

    Carotid artery resection yields a possibility of cure in patients with advanced head and neck carcinoma involving the carotid artery. However, the criteria for the identification of those who are vulnerable to neurologic injury after resection have not been established. Interposition graft covered with a well-vascularized flap could minimize the rate of perioperative morbidity. Particularly, when an extensive resection of the skull base including carotid artery and sigmoid vein, is planned, extracranial-intracranial bypass should be considered to minimize the risks of neurologic morbidity, even if preresection positron emission tomography during balloon test occlusion of internal carotid artery suggested the adequacy of hemispheric collateral blood flow. In these cases, the temporary occlusion of the carotid artery is not an accurate prediction of the morbidity after permanent occlusion. (author)

  15. Clinical studies on cerebral blood flow in chronic subdural hematoma

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Atsuhiro; Akagi, Katsuhito; Horibe, Kunio; Yamasaki, Mami; Yuguchi, Takamichi

    1988-11-01

    Cerebral blood flow (CBF) and clinical symptoms were examined between pre- and post-operations in twenty-four patients with unilateral chronic subdural hematoma. The following results were obtained by intravenous /sup 133/Xe method : 1. There was a reducing tendency of the CBF (hemisphere) on hematoma side, in most cases. While, the groups of headache and disturbances of consciousness did not give a laterality between hematoma and opposite side without the group of hemiparesis. 2. The absolute values of the CBF in the groups of headache and disturbances of consciousness were correlated with the clinical symptoms. In the group of hemiparesis, the laterality between hematoma and opposite side was correlated with the clinical symptoms. 3. In the group of hemiparesis, the F-flow (fast-flow) had sensitive reaction more than the ISI (initial slope index) with symptomatic improvement. 4. It was found that there was not an increase in the absolute value of the CBF, which was under the normal limit between pre- and post-operations in the case without improvement. By SPECT (Method of IMP), the following results were obtained : 1. There was the area of defect at the location of hematoma and the CBF tended to reduce at the subcortical white matter and at the basal ganglia of hematoma side. 2. The CBF of the contralateral hematoma side in the hemisphere of cerebellum was also tended to reduce.

  16. Absolute counting of neutrophils in whole blood using flow cytometry.

    Science.gov (United States)

    Brunck, Marion E G; Andersen, Stacey B; Timmins, Nicholas E; Osborne, Geoffrey W; Nielsen, Lars K

    2014-12-01

    Absolute neutrophil count (ANC) is used clinically to monitor physiological dysfunctions such as myelosuppression or infection. In the research laboratory, ANC is a valuable measure to monitor the evolution of a wide range of disease states in disease models. Flow cytometry (FCM) is a fast, widely used approach to confidently identify thousands of cells within minutes. FCM can be optimised for absolute counting using spiked-in beads or by measuring the sample volume analysed. Here we combine the 1A8 antibody, specific for the mouse granulocyte protein Ly6G, with flow cytometric counting in straightforward FCM assays for mouse ANC, easily implementable in the research laboratory. Volumetric and Trucount™ bead assays were optimized for mouse neutrophils, and ANC values obtained with these protocols were compared to ANC measured by a dual-platform assay using the Orphee Mythic 18 veterinary haematology analyser. The single platform assays were more precise with decreased intra-assay variability compared with ANC obtained using the dual protocol. Defining ANC based on Ly6G expression produces a 15% higher estimate than the dual protocol. Allowing for this difference in ANC definition, the flow cytometry counting assays using Ly6G can be used reliably in the research laboratory to quantify mouse ANC from a small volume of blood. We demonstrate the utility of the volumetric protocol in a time-course study of chemotherapy induced neutropenia using four drug regimens. © 2014 International Society for Advancement of Cytometry.

  17. Nitrite and S-Nitrosohemoglobin Exchange Across the Human Cerebral and Femoral Circulation: Relationship to Basal and Exercise Blood Flow Responses to Hypoxia.

    Science.gov (United States)

    Bailey, Damian M; Rasmussen, Peter; Overgaard, Morten; Evans, Kevin A; Bohm, Aske M; Seifert, Thomas; Brassard, Patrice; Zaar, Morten; Nielsen, Henning B; Raven, Peter B; Secher, Niels H

    2017-01-10

    The mechanisms underlying red blood cell (RBC)-mediated hypoxic vasodilation remain controversial, with separate roles for nitrite () and S-nitrosohemoglobin (SNO-Hb) widely contested given their ability to transduce nitric oxide bioactivity within the microcirculation. To establish their relative contribution in vivo, we quantified arterial-venous concentration gradients across the human cerebral and femoral circulation at rest and during exercise, an ideal model system characterized by physiological extremes of O 2 tension and blood flow. Ten healthy participants (5 men, 5 women) aged 24±4 (mean±SD) years old were randomly assigned to a normoxic (21% O 2 ) and hypoxic (10% O 2 ) trial with measurements performed at rest and after 30 minutes of cycling at 70% of maximal power output in hypoxia and equivalent relative and absolute intensities in normoxia. Blood was sampled simultaneously from the brachial artery and internal jugular and femoral veins with plasma and RBC nitric oxide metabolites measured by tri-iodide reductive chemiluminescence. Blood flow was determined by transcranial Doppler ultrasound (cerebral blood flow) and constant infusion thermodilution (femoral blood flow) with net exchange calculated via the Fick principle. Hypoxia was associated with a mild increase in both cerebral blood flow and femoral blood flow (Pflow during exercise (Pvenous; Parterial; P0.05). These findings suggest that hypoxia and, to a far greater extent, exercise independently promote arterial-venous delivery gradients of intravascular nitric oxide, with deoxyhemoglobin-mediated reduction identified as the dominant mechanism underlying hypoxic vasodilation. © 2016 American Heart Association, Inc.

  18. Role of hypotension in decreasing cerebral blood flow in porcine endotoxemia

    International Nuclear Information System (INIS)

    Miller, C.F.; Breslow, M.J.; Shapiro, R.M.; Traystman, R.J.

    1987-01-01

    The role of reduced arterial blood pressure (MAP) in decreasing cerebral blood flow (CBF) during endotoxemia was studied in pentobarbital-anesthetized pigs. Microspheres were used to measure regional CBF changes during MAP manipulations in animals with and without endotoxin. Endotoxin decreased MAP to 50 mmHg and decreased blood flow to the cortex and cerebellum without affecting cerebral cortical oxygen consumption (CMRo 2 ). Elevating MAP from 50 to 70 mmHg during endotoxemia with norepinephrine did not change cortical blood flow or CMRo 2 but increased cerebellar blood flow. Brain stem blood flow was not affected by endotoxin or norepinephrine. When MAP was decreased to 50 mmHg by hemorrhage without endotoxin, no change in blood flow to cortex, cerebellum, or brain stem was observed from base-line levels. These results suggest that decreased MAP below a lower limit for cerebral autoregulation does not account for the decreased CBF observed after endotoxin

  19. Blood flow and oxygenation in peritendinous tissue and calf muscle during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Green, Sara Marie Ehrenreich

    2000-01-01

    1. Circulation around tendons may act as a shunt for muscle during exercise. The perfusion and oxygenation of Achilles' peritendinous tissue was measured in parallel with that of calf muscle during exercise to determine (1) whether blood flow is restricted in peritendinous tissue during exercise......, and (2) whether blood flow is coupled to oxidative metabolism. 2. Seven individuals performed dynamic plantar flexion from 1 to 9 W. Radial artery and popliteal venous blood were sampled for O2, peritendinous blood flow was determined by 133Xe-washout, calf blood flow by plethysmography, cardiac output...

  20. Blood-brain barrier and cerebral blood flow: Age differences in hemorrhagic stroke

    Directory of Open Access Journals (Sweden)

    Semyachkina-Glushkovskaya Oxana

    2015-11-01

    Full Text Available Neonatal stroke is similar to the stroke that occurs in adults and produces a significant morbidity and long-term neurologic and cognitive deficits. There are important differences in the factors, clinical events and outcomes associated with the stroke in infants and adults. However, mechanisms underlying age differences in the stroke development remain largely unknown. Therefore, treatment guidelines for neonatal stroke must extrapolate from the adult data that is often not suitable for children. The new information about differences between neonatal and adult stroke is essential for identification of significant areas for future treatment and effective prevention of neonatal stroke. Here, we studied the development of stress-induced hemorrhagic stroke and possible mechanisms underlying these processes in newborn and adult rats. Using histological methods and magnetic resonance imaging, we found age differences in the type of intracranial hemorrhages. Newborn rats demonstrated small superficial bleedings in the cortex while adult rats had more severe deep bleedings in the cerebellum. Using Doppler optical coherent tomography, we found higher stress-reactivity of the sagittal sinus to deleterious effects of stress in newborn vs. adult rats suggesting that the cerebral veins are more vulnerable to negative stress factors in neonatal vs. adult brain in rats. However, adult but not newborn rats demonstrated the stroke-indu